AFO Mass Spectrometry Domain Ontology (WD/2025/12)
Ionization method used in precursor activation. [Allotrope]
Fragmentation method used for dissociation or fragmentation. [PSI-MS]
The direction of the scan for scanning analyzers (low to high, or high to low). [PSI-MS]
The scan of the parent mass spectrum generating this MSn spectrum. [Allotrope]
The temperature of the sheath gas. [Allotrope]
K. K. Murray, R. K. Boyd, M. N. Eberlin, G. J. Langley, L. Li and Y. Naito, Pure Appl. Chem., 2013, 85, 1515-1609
Make-up liquid in a sheath flow interface. [IUPAC]
Gas introduced through a tube that is coaxial with the electrospray emitter to pneumatically assist the formation of the sprayed droplets. [IUPAC]
Functional part of a mass spectrometer that detects the ions. [Allotrope]
Functional part of a mass spectrometer that generates the ions. [Allotrope]
The function of a mass spectrometer that separates ions according to their mass-to-charge ratio. [Allotrope]
Whether the sprayer is fed or is loaded with sample once. [PSI-MS]
2024-09-12 Added [IUPAC] attribution, license and rights fields.
Gas used in a spray ion source in addition to the nebulizing gas to aid in solvent removal. [IUPAC]
A. M. Falick, K. F. Medzihradszky, F. C. Walls. Rapid Commun. Mass Spectrom. 4, 318 (1990).
Detector in which the ion beam is focused onto a small area, for example, defined by a collector slit, rather than dispersed by m/z spatially across a focal plane. [IUPAC]
Mass spectrometer that separates ions by m/z in a field-free region after acceleration through a fixed accelerating potential. Ions of the same initial translational energy and different m/z require different times to traverse a given distance in the field-free region. [IUPAC]
A mass spectrometer that uses a laser to illuminate the sample. [Allotrope]
A mass spectrometer that uses an electron ionization source, which consists of a thin strip of metal that is heated electrically to incandescence or a temperature at which it emits free electrons that are accelerated through a potential to an energy where they ionize the sample. [CHMO]
A mass spectrometer that uses multiple stages. [Allotrope]
Device in which m/z selected ions are entrained in an inert carrier gas and subsequently undergo ion/molecule reactions with molecules introduced into the gas flow. [IUPAC]
A collision cell is a chamber in the ion path between m/z separation elements, or between ion source acceleration region and the first analyzer, in tandem mass spectrometry in space configurations. [IUPAC]
A mass spectrometer that has a quadrupole ion trap. [Allotrope]
A device that creates an electric or magnetic field that does not change in time. [PSI-MS]
G. H. Wang, W. Aberth, A. M. Falick. Int. J. Mass. Spectrom. Ion Processes 69, 233 (1986).
K. K. Murray, R. K. Boyd, M. N. Eberlin, G. J. Langley, L. Li and Y. Naito, Pure Appl. Chem., 2013, 85, 1515-1609.
Detector in which a high potential is applied after m/z separation to accelerate the ions and produce an improved signal. [IUPAC]
A mass spectrometer that uses ion kinetic energy spectrometry. [Allotrope]
A mass spectrometer that uses field ionization. [Allotrope]
A mass spectrometer using electrospray ionization. [Allotrope]
electrospray ionization mass spectrometer
transmission quadrupole mass-to-charge analyser
A mass-to-charge analyser that consists of a set of four linear electrodes and allows only ions of a given mass-to-charge ratio, set according to the direct current and radio frequency potentials, to reach a detector. [CHMO]
transmission quadrupole mass-to-charge analyzer
S. D. Tanner, V. I. Baranov, D. R. Bandura. Spectrochim. Acta, Part B 57, 1361 (2002).
Collision cell for removal of interfering ions by ion/neutral reactions in inductively coupled plasma-mass spectrometry. [IUPAC]
Surface that is held at high potential so that ions striking the surface produce secondary charged particles that are subsequently detected. [IUPAC]
For positive ions, the potential is negative and the secondary particles are electrons and negative ions. For nega tive ions, the potential is positive and the secondary particles are positive ions. [IUPAC]
An ion source that produces ions by continuous sputtering of the sample by a glow discharge plasma, which is produced by passing a current of several hundred volts through a low pressiure gas, usually argon. [CHMO]
A surface that is held at high potential so that ions striking the surface produce electrons that are subsequently detected. The high potential is opposite of that of the ion hitting it and that secondary ions formed are opposite as well – hence conversion. [PSI-MS]
Mass spectrometer in which an ion beam accelerated from the ion source is transmitted through a m/z analyzer, or analyzers, to the detector. [IUPAC]
Device for introducing a single sample of a solid or liquid, usually contained in a quartz or other nonreactive sample holder, into a mass spectrometer ion source. [IUPAC]
Continuous moving surface in the form of a wire which passes through an ion source carrying analyte molecules. [PSI-MS]
An ion source that works by sampling an ion beam travelling in a direction orthogonal to the axis of the flight path in the mass-to-charge analyser. [CHMO]
R. M. Smith. Understanding Mass Spectra: A Basic Approach, John Wiley, New York (2004)
Mass spectrometer that consists of an array of four parallel rod electrodes whose centers form the corners of a square and whose opposing electrode pairs are connected. The electric potential applied between the connected pairs of rods is a superposition of a static potential and a sinusoidal radio frequency potential. The motion of an ion in the x-y plane perpendicular to the length direction of the rod electrodes is described by the Mathieu equation whose solutions show that ions in a particular m/z range can be transmitted along the z-axis. [IUPAC]
transmission quadrupole mass spectrometer
Plate where the sample solution is spotted in a MALDI or similar instrument. [PSI-MS]
An electrospray ionization source is a type of ion source that uses an electrospray, an aerosol created by high voltage applied to a liquid solution. [Allotrope]
pyrolysis-field ionization mass spectrometer
A mass spectrometer that uses pyrolysis field ionization. [Allotrope]
pyrolysis field ionization mass spectrometer
double-focusing magnetic sector mass spectrometer
double-focussing magnetic sector mass spectrometer
Mass spectrometer that incorporates a magnetic sector and an electric sector connected in series in such a way that ions with the same m/z but with distributions in both the direction and the translational energy of their motion are brought to a focus. [IUPAC]
adapted from Agilent 6200 series TOF manual.
A resistive narrow cylindrical conduit used to conduct gases and ions and is capable of almost instantanious polarity switching. [Allotrope]
A device for measuring the kinetic energy of charged particles using a retarding field, time-of-flight, or the extent of deflection in an electric or magnetic field. [PSI-MS]
A linear ion trap mass spectrometer where ions are ejected along the radius of the analyzer. [PSI-MS]
An ion mobility mass spectrometry technique based on the superimposition of travelling voltage waves on a radially-confining RF voltage in a gas-filled, stacked-ring ion guide. [PSI-MS]
traveling wave ion mobility mass spectrometer
A device that uses an oscillating electric field and magnetic field to accelerate charged particles. [PSI-MS]
An electron multiplier is a vacuum-tube structure that multiplies incident charges. [Wikipedia]
Ion-to-electron detector in which the ion strikes the surface of an electrode and induces the production of secondary electrons. In turn, these impinge in sequence on dynodes at a more positive electric potential to produce more secondary electrons. This avalanche effect produces an amplification of several orders of magnitude in the final measured current pulse. [IUPAC]
A sector, lens or other ion optics element that produces an electric or magnetic field that extends from its edge. [PSI-MS]
Inlet that uses thermospray ionization. [Allotrope]
Device consisting of pairs of parallel conducting plates, concentric cylinders, or concentric spheres that separate charged particles according to their ratio of translational energy to charge by means of a potential difference applied between the pair. [IUPAC]
Mass spectrometer in which m/z separation is achieved using one or more electric fields that vary with time. [IUPAC]
Higher-order multipoles can also be used in this manner. [IUPAC]
A piece of apparatus that consists of an ion source, a mass-to-charge analyser, a detector and a vacuum system and is used to measure mass spectra. The detector is an ion trap mass-to-charge analyser, which holds the ions in a stable orbit by an electric field. [CHMO]
Device that produces a magnetic field perpendicular to a charged particle beam that deflects the beam to an extent that is proportional to the ratio of particle momentum and charge. [IUPAC]
For a mono-energetic beam, the deflection is proportional to m/z. [IUPAC]
These ion sources use a plasma source or electric discharge to create ions. [Wikipedia]
Set of plates or grid of wires in an ion mobility spectrometer, time-of-flight mass spectrometer, or other mass spectrometer that is used to apply a pulsed electric field with the purpose of selectively deflecting charged particles. [IUPAC]
Conducting cup or chamber that intercepts a charged particle beam and is electrically connected to a current measuring device. [IUPAC]
Gas discharge ion source in which the energy is supplied to the plasma by electromagnetic induction. [IUPAC]
A mass spectrometer that uses ion mobility spectrometry. [Allotrope]
The delivery of a liquid sample into a mass spectrometer for spray or desorption ionization. [PSI-MS]
Series of stacked ring electrodes with progressively decreasing inner diameter to which a combined radio frequency and fixed potential is applied. The resulting field focuses ions travelling along the central axis. [IUPAC]
Two-dimensional Paul ion trap in which ions are confined in the axial dimension by means of a static electric potential. [IUPAC]
Ion trapping device that consists of an outer barrel-like electrode and a coaxial inner spindle-like electrode that form an electrostatic field with a quadro-logarithmic potential distribution. [IUPAC]
The frequency of harmonic oscillations of the orbitally trapped ions along the axis of the electrostatic field is independent of the ion velocity and is inversely proportional to the square root of m/z so that the trap can be operated as a mass analyzer using image current detection and Fourier transformation of the time domain signal. [IUPAC]
The trademarked term Orbitrap has been used to describe a Kingdon trap used as a mass spectrometer. [IUPAC]
A extremely flat surface that holds the sample during a mass spectrometry experiment where the sample is vaporized and ionized using a high-energy pulsed laser whilst being held in a matrix to protect it from direct laser illumination and to separate the sample molecules. The surface of the plate may be chemically functionalised for a specific sample. [CHMO]
matrix assisted laser desorption-ionization plate
The magnetic deflector is a device that deflects charged particles in a magnetic field due to a force equal to qv B where q is the particle charge, v its velocity and B the magnetic field. Magnetic deflection of an ion beam is used for m/z separation in a magnetic sector mass spectrometer. [PSI-MS]
The sample is directly inserted into the ion source, usually on the end of a heatable probe. [PSI-MS]
A ion source that implements tha atmospheric pressure chemical ionization method. [Allotrope]
atmospheric pressure chemical ionization source
Smith, David; Španěl, Patrik (2005). "Selected ion flow tube mass spectrometry (SIFT-MS) for on-line trace gas analysis". Mass Spectrometry Reviews 24 (5): 661–700.
In a flowing afterglow, ions are formed in a flow of inert gas, typically helium or argon. Reagents are added downstream to create ion products and study reaction rates. Flowing-afterglow mass spectrometry is used for trace gas analysis. [Wikipedia]
Component of a time-of-flight mass spectrometer that uses a static electric field to reverse the direction of travel of the ions and improves mass resolution by assuring that ions of the same m/z but different translational energy arrive at the detector at the same time. [IUPAC]
linear quadrupole ion trap mass spectrometer
A mass spectrometer that uses an orthogonal-acceleration ion source. The detector is a quadrupole mass-to-charge analyser, which holds the ions in a stable orbit using an electric field generated by four linear parallel electrodes. [CHMO]
three-dimensional quadrupole ion trap mass-to-charge analyser
A mass-to-charge analyser that uses a three-dimensional quadrupole field (generated by four parallel electrodes) to trap ions in orbits that correspond to their mass-to-charge ratio. [CHMO]
three-dimensional quadrupole ion trap mass-to-charge analyzer
Code for electrospray supply type. [Allotrope]
Three element charged particle lens in which the first and third elements are held at the same voltage. Such a lens produces focusing without changing the translational energy of the particle. [PSI-MS]
mass spectrometer that uses secondary ionization. [Allotrope]
Liquid sample mass spectrometer interface that uses two or more pulleys and a continuous loop of material. Samples are sprayed or deposited from solution onto the belt where they are transported into the vacuum system for vaporization or desorption and ionization. [IUPAC]
M. Karas, D. Bachman, U. Bahr, F. Hillenkamp. Int. J. Mass Spectrom. Ion Processes 78, 53 (1987).
Ionization source for a the formation of gas-phase ions from molecules present in a solid or liquid matrix that is irradiated with a laser. The matrix is a material that absorbs the laser energy and promotes ionization. [IUPAC]
matrix assisted laser desorption ionization source
A detector in which ions strike a conversion dynode to produce electrons that in turn generate photons through a phosphorescent screen that are detected by a photomultiplier. [PSI-MS]
A mass spectrometer that uses the acceleration mass spectrometry technique. [Allotrope]
A mass spectrometer that uses the chemcial ionization. [Allotrope]
An ion source that implements the nanoelectrospray ionization method. [Allotrope]
Inlet for nanospray ionization. [Allotrope]
A mass spectrometer which uses a time-of-flight mass-to-charge analyser to separate ions. Ions introduced into the mass analyzer are accelerated along the axis perpendicular to their initial direction of motion. [CHMO]
orthogonal-acceleration time-of-flight mass spectrometer
Ion-to-electron detector in which the ion strikes the inner surface of a continuous tube device and induces the production of secondary electrons that, in turn, impinge on the inner surfaces of the device to produce more secondary electrons. This avalanche effect produces an increase in the final measured current pulse. [IUPAC]
A mass spectrometer that uses a wedge-shaped magnetic field to separate the total ion beam into discrete ion beams according to the mass-to-charge ratio of the ions. [CHMO]
A mass spectrometer that uses high-field asymmetric waveform ion mobility spectrometry. [Allotrope]
high-field asymmetric waveform ion mobility spectrometer
The secondary ionization source is a source of ions for the secondary ion mass spectrometry. [Allotrope]
A mass spectrometer in which the ions of different m/z are separated by means of crossed electric and magnetic fields in such a way that the selected ions follow a prolate trochoidal path. [IUPAC]
Tandem mass spectrometer comprising two transmission quadrupole mass spectrometers in series, with a (non-selecting) RF-only quadrupole (or other multipole) between them to act as a collision cell. [IUPAC]
laser desorption-ionisation mass spectrometer
A mass spectrometer that uses laser desorption-ionization. [Allotrope]
laser desorption-ionization mass spectrometer
A mass spectrometer that uses a plate to hold the sample in a matrix (such as crystallised dihydrobenzoic acid) whilst it is vaporized and ionized using a high-energy pulsed laser. [CHMO]
matrix assisted laser desorption-ionization mass spectrometer
A piece of apparatus which accelerates a sample of ions so that they all have the same kinetic energy across a field-free drift region of length 1-2 m to a detector, thus separating the ions by their velocity, which is proportional to their mass-to-charge ratio. [CHMO]
A mass spectrometer that uses an inductively coupled plasma torch, an ion source that consists of a torch that is surrounded by a radio frequency generator that ionizes argon gas inside the torch to form a high-temperature (up to 10 000 K) plasma that can be used to ionize analytes. [CHMO]
inductively coupled plasma mass spectrometer
linear quadrapole ion trap mass-to-charge analyser
linear quadrupole ion trap mass analyser
linear quadrupole ion trap mass-to-charge analyser
quadrupole linear ion trap mass spectrometer
A mass-to-charge analyser that uses a two-dimensional quadrupole field (generated by four parallel electrodes) to constrain ions radially into trajectories that correspond to their mass-to-charge ratio. [CHMO]
linear quadrupole ion trap mass-to-charge analyzer
A mass spectrometer that uses field desorption. [Allotrope]
Mass spectrometer designed for mass spectrometry/mass spectrometry. [IUPAC]
Mass spectrometer consisting of one or more magnetic sectors for recording a mass spectrum of a monoenergetic beam of ions. Such instruments may also have one or more electric sectors for energy dispersion that can be arranged for velocity-focusing by compensating for dispersion by the magnetic sector if the beam is not truly monoenergetic. Such a combination provides double focusing of ions of the same m/z, i.e., focusing with respect to both direction and speed. [IUPAC]
A piece of apparatus consisting of paired trapping plates, receiver plates and transmitter plates which provides a magnetic field that coherently excites ions according to their cyclotron frequencies which depend on their mass-to-charge ratio. [CHMO]
A mass spectrometer that uses mass analyzed ion kinetic energy spectrometry. [Allotrope]
mass analyzed ion kinetic energy spectrometer
A linear ion trap mass spectrometer where ions are ejected along the axis of the analyzer. [PSI-MS]
Additional set of four short, cylindrical electrodes, mounted co-linearly with a transmission quadrupole mass spectrometer that is excited with some fraction of the AC potential but not the DC potential applied to the main quadrupole. The Brubaker lens thus acts as a high-pass filter for ion m/z, but the resulting delay in application of the DC potential component also results in a reduction in defocusing by fringe fields and thus significantly improves overall ion transmission efficiency at a given mass resolution. [IUPAC]
All-glass inlet system for ion sources operating under vacuum that can be heated to about 500 °C and allows low vapor pressure materials to be introduced into the mass spectrometer without breaking vacuum. [IUPAC]
Slit installed in a magnetic sector mass spectrometer to allow only those m/z separated ions with a specific m/z into the detector system. [IUPAC]
Reflectron design in which the decelerating/accelerating field is produced without the use of wire-mesh grids. [IUPAC]
This design improves ion transmission but at the cost of a less homogeneous field and thus reduced resolution [IUPAC]
Code indicating the double-focusing mass spectrometer geometry configuration. [Allotrope]
Reflectron that is arranged such that its main axis is coaxial with the ion source and first stage of the time-of-flight analyzer. [IUPAC]
Mass spectrometer based on the principle of ion cyclotron resonance in which an ion in a magnetic field moves in a circular orbit at the cyclotron frequency that is characteristic of its m/z value. Ions are coherently excited to a larger radius orbit using a pulse of radio frequency electric field, and their image charge is detected on receiver plates as a time domain signal. Fourier transformation of the time domain signal results in a frequency domain signal that is converted to a mass spectrum based on the inverse relationship between cyclotron frequency and m/z. [IUPAC]
Fourier transform-ion cyclotron resonance-mass spectrometer
Reflectron designed to provide a decelerating field strength that varies with depth of ion penetration and thus with ion translational energy, permitting energy focusing of ions with a range of translational energies such as those formed as product ions from post-source decay of metastable ions. [IUPAC]
Mass spectrometer in which the ions to be detected, with a selected value of m/z, absorb energy through the effect of a high-frequency electric field and a constant magnetic field perpendicular to the electric field. Maximum energy is gained by the ions that satisfy the cyclotron resonance condition and as a result they are separated from ions of different m/z. [IUPAC]
ion cyclotron resonance-mass spectrometer
Cylindrical chamber containing a buffer gas. Ions introduced at one end are caused to move to the otherend by either a flow of the buffer gas or by a uniform longitudinal electric field. [IUPAC]
Device based on a modification of a direct insertion probe for exposing an involatile sample directly to the electron beam (in an electron ionization source) or to a chemical ionization plasma as in desorption chemical ionization. [IUPAC]
Mass spectrometer interface to inlets including chromatography and spray-based ion sources that enriches the sample by selecting the central part of the effluent or spray using an orifice or skimmer. Particles with a higher forward momentum diverge less from the spray axis for a given radial momentum. [IUPAC]
Ion gate used to transmit ions in a given m/z range. [IUPAC]
Component of a spray ionization interface that consists of a cone with a small orifice through which the spray passes into a differentially pumped chamber. [IUPAC]
A capillary can also be used in place of a cone. [IUPAC]
In interfaces that have both a sampling cone and skimmer, the spray passes first through the sampling cone and then through the skimmer. [IUPAC]
Mass spectrometer in which the ions are directed onto a focal plane detector such as a photographic plate. [IUPAC]
Mass spectrograph based on a double-focusing magnetic analyzer that spatially disperses ions of different m/z values on to an array of Faraday cup detectors, generally used with inductively coupled plasma ion sources for isotopic composition measurements. [IUPAC]
Ion trapping device using a static magnetic field and a static electric potential well. The magnetic field confines the ion motion to circular orbits around the magnetic force line direction, which aligns with the direction of the trap axis, whereas the electric potential well confines the ion motion axially. [IUPAC]
Spray ionization interface in which droplets are dispersed from a pneumatic nebulizer toward a high potential electrode that produces a static charge on the droplets leading to ion formation after solvent evaporation. [IUPAC]
Transmission quadrupole device in which a sinusoidal radio frequency (RF) potential is applied between the connected pairs of opposite rod electrodes in a linear quadrupole, providing a transmission device for all ions with m/z values above a cut-off value. [IUPAC]
Mass analyzer in which m/z separation is achieved using crossed electric and magnetic fields. [IUPAC]
Ion trapping device based on the three-dimensional structure formed by rotating the cross-section of a quadrupole ion trap about the edge perpendicular to the plane of the ring electrode. The resulting trapping region is toroidal. [IUPAC]
Arrangement of two conducting sheets forming a capacitor and giving a radial electrostatic field which is used to deflect and focus ion beams. The degree of deflection varies with the ratio of translational energy to charge. The capacitor may be cylindrical, spherical, or toroidal. [IUPAC]
Quadrupole ion trap whose electrodes form a rectilinear polygon, the simplest form of which consists of two pairs of rectangular electrodes suppli d with radio frequency (RF) potentials and a pair of electrodes to which a DC potential is applied. Slits or apertures in the electrodes allow injection and ejection of charged particles. [IUPAC]
Hybrid mass spectrometer consisting of a transmission quadrupole mass spectrometer coupled to an orthogonal acceleration time-of-flight mass spectrometer. A collision quadrupole is typically inserted between the two mass spectrometers. [IUPAC]
Compact ion and fast atom sources for use when small size and high beam intensity are required, as in fast atom bombardment mass spectrometry. The discharge is produced by electrons oscillating between two cold cathodes in an electric field that possesses a single saddle point. To produce and intensify the plasma the electrons must have long path lengths, achieved by allowing the electrons to have an oscillatory motion in the saddle-shaped electric field between the cathodes separated by the anode. [IUPAC]
Mass spectrometer that combines m/z analyzers of different types to perform tandem mass spectrometry or higher-order MSn experiment. [IUPAC]
Reflectron in which the electric field varies with the square of the distance from the entrance and compensates for kinetic energy spread to all orders. [IUPAC]
Region in a mass spectrometer in which an ion beam is transported from the ion source to the ion optics or from one ion optical element to the next. [IUPAC]
Mass spectrometer used to measure the composition and pressure of gases in an evacuated chamber and to test for leaks in pressurized systems. [IUPAC]
An electrospray 3d ion trap mass spectrometer separates the sample solution by liquid chromatography in combination with electrospray ionization quadrupole ion-trap mass spectrometry. [Allotrope]
electrospray 3d ion trap mass spectrometer
A linear quadrupole ion trap is similar to a quadrupole ion trap, but it traps ions in a two dimensional quadrupole field, instead of a three-dimensional quadrupole field as in a 3D quadrupole ion trap. [Wikipedia]
The trademarked term Orbitrap is used to describe a Kingdon trap used as a mass spectrometer. A Kingdon trap is an ion trapping device that consists of an outer barrel-like electrode and a coaxial inner spindle-like electrode that form an electrostatic field with a quadro-logarithmic potential distribution. [IUPAC]
A combination of two quadrupoles used for controlling beams of charged particles. [Wikipedia]
A. K. Shukla, J. H. Futrell. Mass Spectrom. Rev. 12, 211 (1993)
nert gas used for collisional excitation or a reactive gas used for ion/molecule reactions. [IUPAC]
S. A. Carr, M. J. Huddleston, M. F. Bean. Protein Sci. 2, 183 (1993).
Product ion whose formation reveals structural or compositional information about its precursor ion. [IUPAC]
For example, the phenyl cation in an electron ionization mass spectrum is a diagnostic ion for benzene and derivatives.
S. F. Wong, C. K. Meng, J. B. Fenn. J. Phys. Chem. 92, 546 (1988).
Inert gas that is used to promote the removal of solvent from aerosol particles in spray ionization. [IUPAC]
Serial product ions from dissociation or bimolecular reaction of selected precursor ions where n refers to the number of stages of dissociation or bimolecular reaction in a series of consecutive reactions that involve successive product ions. [IUPAC]
Given the sequential fragmentation scheme: M1+ → M2+ → M3+ → M4+ → M5+ M4+ is the precursor ion of M5+, a 1st-generation product ion of M3+, a 2nd-generation product ion of M2+, and a 3rd-generation product ion of M1+.
J. F. J. Todd. Mass Spectrom. Rev. 10, 3 (1991)
Inert gas used for collisional reduction of the internal or translational energy of ions, such as in ion traps. [IUPAC]
Ion formed by the interaction of a precursor ion with one or more atoms or molecules to form an ion containing all the constituent atoms of the precursor ion as well as the additional atoms from the associated atoms or molecules. [IUPAC]
For example, a Na+ adduct of a molecule (M) that is represented as [M + Na]+.
A. P. Bruins, T. R. Covey, J. D. Henion. Anal. Chem. 59, 2642 (1987)
B. Thomson, J. Iribarne, P. Dziedzic. Anal. Chem. 54, 2219 (1982)
C. M. Whitehouse, R. N. Dreyer, M. Yamashita, J. B. Fenn. Anal. Chem. 57, 675 (1985)
Stream of inert gas, often heated, that is used in an electrospray or other spray ionization source to aid in the evaporation of solvent from the sprayed particles. The flow of the gas is in the direction opposite to that of the spray. [IUPAC]
J. Adams. J. Am. Soc. Mass Spectrom. 3, 473 (1992).
K. K. Murray, R. K. Boyd, M. N. Eberlin, G. J. Langley, L. Li and Y. Naito, Pure Appl. Chem., 2013, 85, 1515-1609, 10.1351/PAC-REC-06-04-06.
M. Bursey. Mass Spectrom. Rev. 10, 1 (1991).
P. Price. J. Am. Soc. Mass Spectrom. 2, 336 (1991).
Ion formed as the product of a reaction involving a particular precursor ion. [IUPAC]
The reaction can be of different types including unimolecular dissociation to form fragment ions, an ion/molecule reaction, or simply involve a change in the number of charges.
The term daughter ion is deprecated. [IUPAC]
Product ion that results from the dissociation of a precursor ion. [IUPAC]
Ion enriched in an isotope in which the abundance of the particular nuclide is increased above the abundance at which it occurs in a reference, usually a naturally occurring sample. [IUPAC]
Atomic or molecular species with the same nominal mass but different exact masses. [IUPAC]
In the case of atoms, this is equivalent to different nuclides of equal mass number. [IUPAC]
This term is used in meteorology to denote lines connecting points of equal atmospheric pressure. [IUPAC]
Chemical labeling reagents used for relative or absolute quantitation in proteomics, based on covalent labeling of the N-terminus and side-chain amines of peptides from protein digestions with tags of varying mass. [IUPAC]
isobaric tag for relative and absolute quantitation
Any ion containing one or more of the less abundant naturally occurring isotopes of the elements that make up its structure. [IUPAC]
Isobaric ions are isobars that all carry an electric charge. [IUPAC]
Fragment ion containing the peptide C-terminus formed upon dissociation of a peptide ion at the peptide backbone C–N bond. [IUPAC]
Fragment ion containing the peptide C-terminus formed upon dissociation of a peptide ion at the peptide backbone C–C bond. [IUPAC]
Electrons ejected from a sample surface as a result of bombardment by a primary beam of atoms, ions, electrons, or photons. [IUPAC]
High-energy product ion of a protonated peptide formally equivalent to a z-ion that has lost the part of the N-terminal side-chain starting at the γ-carbon (if any). [IUPAC]
Stable ion whose structure or elemental formula is known with certainty. These ions are formed by direct ionization of a molecule of known structure or elemental formula, and are used to verify by comparison the structure or thermochemistry of an unknown ion or to calibrate the m/z scale of the mass spectrometer. [IUPAC]
Fragment ion containing the peptide C-terminus formed upon dissociation of a peptide ion at the peptide backbone N–C bond. [IUPAC]
High-energy product ion of a protonated peptide formally equivalent to a y-ion with the ionizing proton on the N-terminus, but with elimination of HR from the N-terminus where R is the side-chain on the C-atom of the N-terminal residue, to give a (H2N+=CH–CO—-) structure. [IUPAC]
Photoionization of an atom or molecule in which two or more photons are absorbed. [IUPAC]
Chemical ionization that results in the formation of negative ions. [IUPAC]
Handbook of Stable Isotope Analytical Techniques. Elsevier. 2004. ISBN 0-444-51114-8
Norton, RB et al. (1966). "Ion-neutral reactions in the Martian ionosphere". Planetary and Space Science 14 (10): 969–978
An ion source immersed in a flow of helium or other inert buffer gas that carries the ions through a meter-long reactor at pressures around 100 Pa. [PSI-MS]
Laser desorption ionization mass spectrometry, particularly emphasizing spatially resolved composition information. [IUPAC]
atmospheric pressure photoionization mass spectroscopy
A type of mass spectrometry where the sample is irradiated with an ultraviolet laser at atmospheric pressure. The sample absorbs one or more photons resulting in ionization. [CHMO]
atmospheric pressure photoionization mass spectrometry
microelectrospray ionization mass spectroscopy
A type of mass spectrometry where the sample is ionized by forcing a solution (usually in an organic solvent) of the sample through a small heated capillary (at a flow rate of 1 L min-1) into an electric field to produce a very fine mist of charged droplets. [CHMO]
microelectrospray ionization mass spectrometry
selected ion flow tube mass spectroscopy
A type of mass spectrometry where the sample is ionized by introducing it into a tube containing fast flowing He gas and ions such as H3O+, NO+ and O2+. [CHMO]
selected ion flow tube mass spectrometry
Variant of fast atom bombardment in which the mixture of analyte and liquid matrix is continuously supplied to the sample probe tip. [IUPAC]
A type of mass spectrometry where the sample is irradiated with a resonant laser (a laser beam with a wavelength that corresponds to an atomic transition in the sample). The sample absorbs two or more photons resulting in ionization. [CHMO]
A type of mass spectrometry where the sample is ionized by a vacuum spark discharge, which is generated by a pulsed high (25-100 kV) potential difference between two electrodes. [CHMO]
A type of mass spectrometry where the sample is bombarded with a stream of primary mass-selected particles and the secondary elemental ions (usually H+, D+ or He+) ejected from the sample are detected. [CHMO]
A type of mass spectrometry where the sample is irradiated with an ultraviolet laser. The sample absorbs one or more photons resulting in ionization. [CHMO]
atmospheric-pressure laser induced mass spectrometry
atmospheric-pressure laser ionization mass spectroscopy
Mass spectrometry using atmospheric-pressure laser ionization. [Allotrope]
atmospheric-pressure laser ionization mass spectrometry
A type of mass spectrometry where the sample is ionized by interaction with a high electric field. [CHMO]
Spectra is combined by calculating the mean of the spectra. [PSI-MS]
A type of spectrometry where the sample spotted onto paper then solvent is applied and an electrically charged solvent is generated upon application of a high voltage. The ions are then characterised by their mass-to-charge ratio and relative abundance. [CHMO]
Ionization of any species by the interaction of a focused beam of ions, with a translational energy of several thousand eV, with a solid or liquid sample. [IUPAC]
For a liquid sample, fast ion bombardment is the same as liquid secondary ionization. [IUPAC]
Electrospray ionization at a very low solvent flow rate, typically hundreds of nanoliters per minute of sample solution or lower, often without the use of an external solvent delivery system. [IUPAC]
Nanospray should only be used to describe the commercial product. [IUPAC]
A type of mass spectrometry where the sample (which is held in a liquid matrix) is bombarded with a stream of primary noble gas atoms and the secondary ions ejected from the sample are detected. [CHMO]
A mass spectrometry using loop injection. [Allotrope]
Dissociation of an ion after collisional excitation. [IUPAC]
A mass spectrometry technique in which m/z separation using one or more electric fields that vary with time. [CHMO]
Z. Takáts, J.M. Wiseman, and R.G. Cooks, J. Mass Spectrom. 40, 1261–1275 (2005)
An ionization method where charged solvent droplets which are formed by forcing the solvent through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field are directed at the sample surface. The droplets form a thin film on the sample surface, dissolving the analyte of interest. [CHMO]
Any type of mass spectrometry where the mass-to-charge ratio of the sample ions is measured whilst the ions are held in a stable orbit by an electric or magnetic field. [CHMO]
electrospray ionization mass spectroscopy
Any type of spectrometry where the sample is ionized by forcing a solution (usually in an organic solvent) of the sample through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field to produce a very fine mist of charged droplets. The ions are then characterised by their mass-to-charge ratio and relative abundance. [CHMO]
electrospray ionization mass spectrometry
Acquisition and study of the spectra of the product ions or precursor ions of m/z selected ions, or of precursor ions of a selected neutral mass loss. [IUPAC]
MS/MS can be accomplished using instruments incorporating more than one analyzer (tandem mass spectrometry in space) or in trap instruments (tandem mass spectrometry in time). [IUPAC]
Spectra is combined by calculating the median of the spectra. [PSI-MS]
A process of removal of varying intensities generated due to variable energy absorption before further processing can take place. Baseline reduction facilitates meaningful comparison between intensities of m/z values. [PSI-MS]
The ionization of material in a solid sample by bombarding it with ionic or neutral atoms formed as a result of the fission of a suitable nuclide, typically 252Cf. [PSI-MS]
pneumatically-assisted electrospray ionization mass spectrometry
pneumatically-assisted electrospray ionization mass spectroscopy.
A type of mass spectrometry where the sample is ionized by forcing an aqueous solution of the sample through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field to produce a very fine mist of charged droplets. [CHMO]
electrospray ionization laser desorption mass spectrometry
A type of mass spectrometry where neutral molecules are desorbed from the sample (usually biological) using a nitrogen laser and then ionized by collision with charged solvent droplets which are formed by forcing the solvent through a small heated capillary into an electric field. [CHMO]
electrospray-assisted laser desorption-ionization mass spectrometry
A type of mass spectrometry that uses sinusoidal radio frequency fields (in the x- and y- direction, differing in phase by 90 deg.) during ion detection. The ions of a particular mass travel in a helix and impact an ion detector, generating a pattern consisting of a set of concentric circles. [CHMO]
Mass spectrometry measurement in which the sample is introduced into the ion source of the mass spectrometer as a collimated beam of molecules with a narrow velocity distribution. [IUPAC]
matrix-assisted laser desorption ionization (MALDI) MS
matrix-assisted laser desorption-ionization mass spectroscopy
Any type of mass spectrometry where the sample (usually a large organic molecule or biomolecule) is vaporized and ionized using a high-energy pulsed laser. The sample is held in a matrix (such as crystallised dihydrobenzoic acid) to protect it from direct laser illumination and to separate the sample molecules. [CHMO]
matrix-assisted laser desorption-ionization mass spectrometry
desorption electrospray ionization mass spectroscopy
A type of mass spectrometry where the sample is ionized by directing charged solvent droplets (which are formed by forcing the solvent through a small heated capillary into an electric field) at the sample surface. The droplets form a thin film on the sample surface, dissolving the analyte of interest. [CHMO]
desorption electrospray ionization mass spectrometry
Procedure by which neutral species are formed from m/z selected ions by charge transfer to a collision gas or by dissociation. The neutral species are separated from the remaining ions and ionized through collisions with a second gas. [IUPAC]
neutralization-reionization mass spectrometry
A type of mass spectrometry where the sample (usually a large organic molecule or biomolecule) is vaporized and ionized using a high-energy pulsed laser. The sample is held in a sol-gel matrix to protect it from direct laser illumination and to separate the sample molecules. [CHMO]
sol-gel-assisted laser desorption-ionization mass spectrometry
A type of mass spectrometry where ionization is achieved by loading the sample onto a heated filament. [CHMO]
Any type of mass spectrometry where the sample is illuminated with a laser. [CHMO]
Secondary ion mass spectrometry analysis with primary ion current density sufficiently high for use in analysis of sample surface layers in the depth direction. [IUPAC]
ion cyclotron resonance mass spectroscopy
ion-cyclotron-resonance mass spectrometry
ion-cyclotron-resonance mass spectroscopy
A type of mass spectrometry where the mass-to-charge ratio of the sample ions is determined by measuring their cyclotron frequency (the frequency at which they precesses in a fixed magnetic field). [CHMO]
ion cyclotron resonance mass spectrometry
Method used to combine the mass spectra. [PSI-MS]
nanoelectrospray ionization mass spectroscopy
A type of mass spectrometry where the sample is ionized by forcing a solution (usually in an organic solvent) of the sample through a small heated capillary (at a flow rate of nL min-1) into an electric field to produce a very fine mist of charged droplets. [CHMO]
nanoelectrospray ionization mass spectrometry
A triple quadrupole mass spectrometry is tandem mass spectrometry using two quadropole mass analyzers in series with a (non-mass-resolving) radio frequency (RF)–only quadrupole between them to act as a cell for collision-induced dissociation. This configuration is often abbreviated QqQ. [Wikipedia]
An ionization method where a plasma (a partially ionized gas - such as Ar - containing free electrons) is directed onto the sample surface causing desorption of sample molecules from the surface and subsequent ionization. [CHMO]
dynamic neutral particle mass spectrometry
dynamic neutral particle mass spectroscopy
secondary neutral atom mass spectroscopy
secondary neutral particle mass spectrometry
secondary neutral particle mass spectroscopy
sputtered neutral atom mass spectrometry
sputtered neutral atom mass spectroscopy
sputtered neutral particle mass spectroscopy
Mass spectrometry technique in which neutral species ejected from a sample surface as a result of bombardment by a primary beam of atoms or ions are ionized, most often by photoionization, prior to analysis. [IUPAC]
secondary neutral atom mass spectrometry
2024-09-12 Added license and rights fields.
Ionization of an atom or molecule by a photon, written M + hν → M+• + e–. [IUPAC]
Multiphoton ionization in which the ionization cross section is significantly enhanced because theenergy of the incident photons is resonant with an intermediate excited state of the neutral. [IUPAC]
resonance enhanced multiphoton ionization
Ionization of any species by the interaction of a focused beam of ions or atoms with a sample that is dissolved in a solvent matrix. [IUPAC]
Mass spectrometry technique in which the sample is heated to the point of decomposition and the gasphase decomposition products are characterized by mass spectrometry. [IUPAC]
D. Zakett, A. E. Schoen, R. W. Kondrat, R. G. Cooks. J. Am. Chem. Soc. 101, 6781 (1979).
Scan used to generate a constant neutral loss spectrum. [IUPAC]
extractive electrospray ionization mass spectroscopy
A type of mass spectrometry where a neutral sample, in the form of a gas or aerosol flow, is ionized by directing it into a plume of charged droplets, generated by forcing a solution of pure solvent through a small heated capillary (at a flow rate of 1-10 µL min-1) into an electric field. [CHMO]
extractive electrospray ionization mass spectrometry
Mass spectrometry in which the product ions are collected after a time delay, which allows the observation of lower energy fragmentation processes after precursor ion activation. [PSI-MS]
A type of mass spectrometry where the mass-to-charge ratio of the sample ions is measured whilst the ions are held in a stable orbit by an electric field generated by four parallel electrodes. The voltage is a combination of Radio Frequency (RF) and Direct Current (DC). [CHMO]
Any ionization method when the sample is ionized in a plasma - a partially ionized gas (such as Ar) containing free electrons. [CHMO]
Procedure associated with Fourier transform-ion cyclotron resonance-mass spectrometers to facilitate ion/neutral reactions such as low-energy collision-induced dissociation in which a radio-frequency electric field, slightly off-resonance with respect to the cyclotron frequency of the reactant ion, cyclically accelerates and decelerates the reactant ion that is confined in the Penning ion trap. As a consequence, the orbit does not exceed the dimensions of the ion trap but maintains a high average translational energy for an extended time that activates an ion/neutral process. [IUPAC]
Procedure by which translational energy spectra are obtained from a sector mass spectrometer that incorporates at least one magnetic sector plus one electric sector in reverse geometry (a magnetic sector followed by an electric sector). [IUPAC]
In this context, kinetic energy is interpreted as translational rather than vibrational or rotational kinetic energy. [IUPAC]
The accelerating potential, V, and the magnetic flux density, B, are set at fixed values to m/z select the precursor ions, which are then allowed to dissociate or to react in a field-free region between the two sectors. The translational energy-to-charge ratios of the various product ions are analyzed by scanning the electric sector field E. The width of a product ion spectral peak is related to the kinetic energy release distribution for the dissociation process. [IUPAC]
mass analyzed ion kinetic energy spectrometry
A mass spectrometry method using a direct inlet. [Allotrope]
Spray ionization in which a liquid is flowed through a heated capillary to produce a spray of droplets and solvent vapor. Ions are formed due to the statistical imbalance of charges in the droplets or by a heated filament. [IUPAC]
R. G. Cooks, Z. Ouyang, Z. Takats, J. M. Wiseman. Science 311, 1566 (2006)
Desorption of molecules and formation of ions outside the mass spectrometer directly from samples in their native environment with no or minimal sample preparation. [IUPAC]
Examples are desorption electrospray ionization (DESI) and direct analysis in real time (DART).
Atmospheric pressure chemical ionization in which the reactant ions are generated by photo-ionization. [PSI-MS]
Spray ionization process in which either cations or anions in solution are transferred to the gas phase via formation and desolvation at atmospheric pressure of a stream of highly charged droplets that result from applying a potential difference between the tip of the electrospray needle containing the solution and a counter electrode. When a pressurized gas is used to aid in the formation of a stable spray, the term pneumatically assisted electrospray ionization is used. [IUPAC]
pneumatically assisted electrospray ionization
Technique in which a focused beam of primary ions produces secondary ions by sputtering from a solid surface. The secondary ions are analyzed by mass spectrometry. [IUPAC]
electrospray-assisted laser desorption-ionization
An ionization method where neutral molecules are desorbed from the sample (usually biological) using a nitrogen laser and then ionized by collision with charged solvent droplets which are formed by forcing the solvent through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field. [CHMO]
laser desorption electrospray ionization
Formation of gas phase ions from a solid or liquid sample surface upon activation by heat, strong electric field, particles, droplets, or photon bombardment. [IUPAC]
Y.-F. Liu, Z.-Y. Guo, X.-Q. Liu, T. Qu, J.-L. Xie. Pure Appl. Chem. 66, 305 (1994).
Mass spectrometry technique in which atoms and molecules from a sample are ionized, accelerated to MeV energies and separated according to their momentum, charge, and energy, allowing high discrimination for measurement of isotope abundances. [IUPAC]
A technique specific to reflectron time-of-flight mass spectrometers where product ions of metastable transitions or collision-induced dissociations generated in the drift tube prior to entering the reflectron are m/z separated to yield product ion spectra. [PSI-MS]
in-source collision-induced dissociation
in-source collisionally activated dissociation
Collisionally activated dissociation that is caused by collisions in the region between the nozzle and skimmer of an atmospheric pressure ionization source such as electrospray or atmospheric pressure chemical ionization. [IUPAC]
laser desorption-ionization mass spectroscopy
A type of mass spectrometry where the sample is vaporised and ionized using a high-energy pulsed laser. [CHMO]
laser desorption-ionization mass spectrometry
F. W. McLafferty, F. Turecek. Interpretation of Mass Spectra, University Science Books, Mill Valley, CA (1993).
Formation of gas-phase ions accompanied by extensive fragmentation. [IUPAC]
An ionization method when the sample is ionized, at atmospheric pressure, in a plasma (a partially ionized gas - such as Ar - containing free electrons) which has been generated by passing an electrical discharge between two electrodes. [CHMO]
atmospheric pressure glow discharge ionization
Any type of mass spectrometry where the sample ions are directed into magnetic field, the orientation of which is perpendicular to the beam. The magnetic field forces the charged particles into different circular trajectories, the radii of which depend on the strength of the magnetic field, the accelerating voltage, and the mass of the ion. [CHMO]
Ionization via electron removal that occurs through the energy transfer from a neutral species (N) internally excited to a metastable state (such as a high Rydberg state) to a neutral species (M) with lower ionization energy, as represented by the following reaction: N* + M → N + M+• + e–. [IUPAC]
Penning ionization differs from chemi-ionization in that no chemical change is involved. [IUPAC]
Atmospheric pressure chemical ionization in which the low-temperature plasma is not generated by a corona discharge but by a device consisting of two electrodes with at least one dielectric layer that separates the electrode from the plasma. [IUPAC]
pyrolysis field desorption mass spectroscopy
pyrolysis-field desorption mass spectrometry
pyrolysis-field desorption mass spectroscopy
A type of mass spectrometry where the sample is pyrolysed then deposited on a solid surface known as an 'emitter' and ionized by interaction with a high electric field. [CHMO]
pyrolysis field desorption mass spectrometry
Formation of ions from a solid material by an intermittent electric discharge. [IUPAC]
A type of mass spectrometry where the relative abundance of non-radioactive isotopes in a sample is determined. [CHMO]
Activation of the precursor ion in mass spectrometry. [Allotrope]
electron capture negative ionization mass spectroscopy
resonant electron capture negative ionization mass spectrometry
resonant electron capture negative ionization mass spectroscopy
A type of mass spectrometry where the sample is ionized by interaction with thermal electrons (electrons with energy 0.1 eV or less). [CHMO]
electron capture negative ionization mass spectrometry
D. E. Games. Chem. Phys. Lipids 21, 389 (1978).
The formation of gas-phase ions without extensive fragmentation. [IUPAC]
A type of mass spectrometry where a liquid sample passes through a desolvation chamber producing a beam of microscopic solid particles. [CHMO]
dual inlet isotope ratio mass spectrometry
A type of mass spectrometry where purified gas obtained from a sample is alternated rapidly with a standard gas (of known isotopic composition) by means of a system of valves, so that a number of comparative measurements are made of both gases. The relative abundance of isotopes in a sample is then determined. [CHMO]
dual-inlet isotope ratio mass spectrometry
elemental analyser isotope ratio mass spectrometry
elemental analyser isotope ratio mass spectroscopy
elemental analysis isotope ratio mass spectroscopy
A type of mass spectrometry where the sample is first subject to elemental analysis (dropped onto a heated reactor which contains an oxidant - such as copper and chromium oxide - and combusted at 900 C to produce N2, NOx, H2O and CO2 which are reduced in a stream of helium) before the relative abundance of isotopes in the sample is determined. [CHMO]
elemental analysis isotope ratio mass spectrometry
Matrix-assisted laser desorption ionization in which the matrix is covalently linked to the target surface. [PSI-MS]
Any type of mass spectrometry where the 'exact' mass of the molecular ions in the sample is determined as opposed to the 'nominal' mass (the number of protons and neutrons). [CHMO]
Measurement and study of the relative abundances of the different isotopes of an element in a material using a mass spectrometer. [IUPAC]
The removal of electrons from any species by interaction with a high electric field. [PSI-MS]
Process in which ions are ejected from a sample surface as a result of bombardment by a primary beam of atoms or ions. [IUPAC]
The chemical degradation of a sample by thermal energy in which the reactor is located within the ion source of a mass spectrometer. [CHMO]
Zoom scan is a type of scan mode, where data with improved resolution is acquired. This is typically achieved by scanning a more narrow scan window or scanning with a lower scan rate. [PSI-MS]
The determination of the mass of an ion based on the mass spectral peaks that represent multiple-charge ions. [PSI-MS]
Process in which one or more electrons are removed from or added to a molecule without a change in the positions of the atoms. [IUPAC]
Such a frozen nuclei process is called a Franck–Condon process in optical spectroscopy. [IUPAC]
The resulting ion is typically in an excited vibrational state. [IUPAC]
An ionization method in which a corona discharge is used to direct a liquid spray (composed of an inert, high velocity gas and solvent ions) onto the sample surface. [CHMO]
desorption atmospheric pressure chemical ionization
orthogonal accelerator mass spectrometry
A type of mass spectrometry where the sample is ionized and the ions are accelerated to very high kinetic energies by an ion source that works by sampling an ion beam travelling in a direction orthogonal to the axis of the flight path in the mass-to-charge analyser. [CHMO]
orthogonal acceleration mass spectrometry
Electrospray ionization at a low solvent flow rate, typically several microliters per minute or lower, where a pump is used to provide the sample flow. [IUPAC]
far-infrared laser magnetic resonance spectroscopy
laser magnetic resonance (LMR) at far-infrared wavelengths
A type of spectroscopy where the energy levels of paramagnetic species (such as HCN) are tuned into resonance with a far-infrared laser source in order to investigate rotational transitions. [CHMO]
far-infrared magnetic resonance spectroscopy
Fragmentation that results from the collision of an ion with a surface. [IUPAC]
low pressure chemical ionization mass spectrometry
low pressure chemical ionization mass spectroscopy
A type of mass spectrometry where the sample is ionized by interaction (electron or proton transfer) with reagent (N2, O2, H2O) gaseous ions at low pressure. Reagent ions are produced by electron ionization. [CHMO]
Ionization process in which two atoms or molecules, one or both of which is in an excited state, react to form a single positive ion and an electron. [IUPAC]
An ionization method where neutral molecules are desorbed from the sample (usually biological and held in an organic acid matrix) using a nitrogen laser and then ionized by collision with charged solvent droplets which are formed by forcing the solvent through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field. [CHMO]
matrix-assisted laser desorption electrospray ionization
pyrolysis field ionization mass spectroscopy
pyrolysis-field ionization mass spectrometry
pyrolysis-field ionization mass spectroscopy
A type of mass spectrometry where the sample is pyrolyzed then ionized by interaction with a high electric field. [CHMO]
pyrolysis field ionization mass spectrometry
Scan that determines, in a single experiment, the m/z values of product ions that are produced by the reaction of a selected precursor ion with a user-specified m/z value. [IUPAC]
A type of mass spectrometry where the sample is ionized by electrons (energy 70 eV) which have been emitted from a glowing filament and accelerated through an electric field. [CHMO]
The formation of gas-phase ions from a material deposited on a solid surface in the presence of a high electric field. Because this process may encompass ionization by field ionization or other mechanisms, it is not recommended as a synonym for field desorption ionization. [PSI-MS]
Because this process probably encompasses ionization by field ionization in conjugation with other mechanisms of ionization, the term field desorption ionization, despite its widespread use, is imprecise and therefore not recommended. [IUPAC]
A collision-induced dissociation process wherein the projectile ion has the translational energy higher than approximately 1000 eV. [PSI-MS]
high-energy collision-induced dissociation
Collision-induced dissociation process wherein the precursor ion has laboratory-frame translational energy lower than a given value, often taken to be 1 keV. [IUPAC]
This process can be carried out under single collision conditions but typically requires multiple collisions and the collisional excitation is cumulative. [IUPAC]
low-energy collision-induced dissociation
secondary electron emission mass spectroscopy
Any type of mass spectrometry where a surface is bombarded with sample ions and the secondary electrons emitted are detected. [CHMO]
secondary electron emission mass spectrometry
Ionization of molecules initiated by a beam of neutral atoms with translational energies in the keV range. Labile molecules susceptible to dissociation are dissolved in an involatile liquid matrix that absorbs the energy of the bombarding atoms to form a selvedge region above the liquid surface in which ionization of the molecules occurs. [IUPAC]
Positive ions (e.g., protonated or cationized molecules) or negative ions (e.g., deprotonated molecules) are formed depending on the polarity of ionization. [IUPAC]
Any type of mass spectrometry where sample ions with different masses are accelerated to the same (known) kinetic energy and the time taken for each ion to reach a detector at a known distance is measured. This time is dependent on the mass-to-charge ratio of the ion. [CHMO]
P. Price. J. Am. Soc. Mass Spectrom. 2, 336 (1991)
Scan that determines, in a single experiment, the m/z values of precursor ions that react to produce a product ion with a user-selected m/z value. [IUPAC]
Formation of gas-phase ions by the interaction of a laser with a solid or liquid material. [IUPAC]
Spectra are overlayed on plot. [Allotrope]
D. I. Carroll, I. Dzidic, R. N. Stillwell, K. D. Haegele, E. C. Horning. Anal. Chem. 47, 2369 (1975).
E. Rosenberg. J. Chromatogr., A 1000, 841 (2003).
Any ionization process in which ions are formed in the gas phase at atmospheric pressure. [PSI-MS]
Atmospheric pressure ionization is not a synonym for atmospheric pressure chemical ionization. [IUPAC]
Technique to create excitation waveforms for ions in Fourier transform-ion cyclotron resonance-mass spectrometers or Paul ion traps. An excitation waveform in the time-domain is generated by taking the inverse Fourier transform of an appropriate frequency-domain programmed excitation spectrum, in which the resonance frequencies of ions to be excited are included. [IUPAC]
This procedure may be used for selection of precursor ions in MSn experiments. [IUPAC]
stored waveform inverse fourier transform
multi photon ionization mass spectroscopy
multiphoton ionization mass spectroscopy
A type of mass spectrometry where the sample is irradiated with an ultraviolet laser. The sample absorbs two or more photons resulting in ionization. [CHMO]
multiphoton ionization mass spectrometry
surface-assisted laser desorption-ionization mass spectrometry
A type of mass spectrometry where the sample (usually a large organic molecule or biomolecule) is vaporized and ionized using a high-energy pulsed laser. The sample is mixed with a matrix compound (such as crystallised dihydrobenzoic acid) and deposited on a surface, with some chemical functionality, to protect it from direct laser illumination and to separate the sample molecules. [CHMO]
surface-enhanced laser desorption-ionization mass spectrometry
An ionization method where the sample is vaporised using a high-energy pulsed laser and then ionized by forcing a solution (usually in an organic solvent) of it through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field to produce a very fine mist of charged droplets. [CHMO]
Data processing methods applicable to mass spectrometry results. [Allotrope]
Energy focusing of ions formed in the gas phase in a time-of-flight mass spectrometer that is accomplished by introducing a time delay between the formation of the ions and the application of the accelerating potential pulse. [IUPAC]
Any mass spectrometry technique where the sample is ionized at low or ambient temperature. [CHMO]
A method of analysis in which a beam of ions is separated according to the ratio of its translational energy to charge. [PSI-MS]
Any type of mass spectrometry where the sample is ionized in a plasma (a partially ionized gas - such as Ar - containing free electrons). [CHMO]
Quantitative mass spectrometry technique in which an isotopically enriched compound is used as a surrogate internal standard. [IUPAC]
matrix-assisted laser desorption-ionization imaging mass spectroscopy
The collection of spatially resolved mass spectra of a sample during microscopy where a pulse laser is used to produce both ionization and vapourization and the sample is held in a matrix (such as dihydrobenzoic acid) to protect it from direct laser illumination and to separate the sample molecules. The spectra are used to visualise the spatial distribution of (typically) biomolecules by their molecular masses. [CHMO]
matrix-assisted laser desorption-ionization imaging mass spectrometry
An ionization method where the sample is ionized by a corona discharge within a He atmosphere. [CHMO]
Direct analysis in real time is a proprietary term indicating the formation of ions from a solid or liquid sample at atmospheric pressure through the interaction of a gas stream containing internally excited atoms or molecules with the surface. The excited-state species are typically formed in a glow discharge in helium or nitrogen. The term should only be used to describe the commercial product. [IUPAC]
proton transfer reaction mass spectroscopy
A type of mass spectrometry where the sample is ionized by introducing it into a tube containing fast flowing He gas and H3O+ ions. [CHMO]
proton transfer reaction mass spectrometry
A process that involves precursor ion activation at high Q, a time delay to allow the precursor to fragment, then a rapid pulse to low Q where all fragment ions are trapped. The product ions can then be scanned out of the ion trap and detected. [PSI-MS]
Class of matrix-free laser desorption ionization techniques for biological macromolecules. [IUPAC]
An example is desorption ionization on silicon (DIOS). [IUPAC]
surface-assisted laser desorption/ionization
A type of mass spectrometry where the sample is irradiated with a resonant laser (a laser beam with a wavelength that corresponds to an atomic transition in the sample). The sample absorbs one or more photons resulting in ionization. [CHMO]
resonance-enhanced multiphoton ionization mass spectrometry
Procedure used to form chemically selective images of an object based on the mass spectrometric detection of ions desorbed from its surface. [IUPAC]
F. L. King, J. Teng, R. E. Steiner. J. Mass Spectrom. 30, 1061 (1995).
J. Coburn, W. Harrison. Appl. Spectrosc. Rev. 17, 95 (1981).
Formation of ions from gaseous atoms or molecules or from the vapor of a solid sample at the cathode by applying a potential difference between two electrodes immersed in a low-pressure inert gas environment. [IUPAC]
Ionization of a neutral through contact with a high-temperature surface. [IUPAC]
Chemical ionization that takes place at atmospheric pressure as opposed to the reduced pressure is normally used for chemical ionization. [PSI-MS]
atmospheric pressure chemical ionization
secondary electrospray ionization mass spectroscopy
A type of mass spectrometry where the sample ionized by spraying it with a very fine mist of charged droplets which was produced by forcing a solvent through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field. [CHMO]
secondary electrospray ionization mass spectrometry
continuous flow isotope ratio mass spectrometry
A type of mass spectrometry where the relative abundance of isotopes in a sample is determined. Measurements are taken immediately after sample preparation and separately to the standard gas. [CHMO]
continuous-flow isotope ratio mass spectrometry
surface enhanced laser desorption ionization
Variant of matrix-assisted laser desorption/ionization (MALDI) in which the matrix is replaced by a surface coating of a chromatographic stationary phase designed to selectively retain different subsets of proteins or peptides from a mixture depending on their physico-chemical properties or biochemical affinity characteristics. [IUPAC]
Originally this technique was named surface-enhanced affinity capture (SEAC) to distinguish it from surface-enhanced neat desorption (SEND) where the surface coating is designed to increase the efficiency of laser desorption. [IUPAC]
surface-enhanced laser desorption/ionization
Ionization of a neutral when it interacts with a solid surface with an appropriate work function and temperature. [IUPAC]
M. Constapel, M. Schellenträger, O. J Schmitz, S. Gäb, K. J Brockmann, R. Giese, Th Benter (2005) "Atmospheric�?pressure laser ionization: a novel ionization method for liquid chromatography/mass spectrometry". Rapid Communications in Mass Spectrometry 19 (3)
Matthias Lorenz, Ralf Schiewek, Klaus J. Brockmann, Oliver J. Schmitz, Siegmar Gäb, Thorsten Benter (2008). "The Distribution of Ion Acceptance in Atmospheric Pressure Ion Sources: Spatially Resolved APLI Measurements.". Journal of the American Society for Mass Spectrometry 19 (3): 400–410.
Atmospheric pressure laser ionization is an atmospheric pressure ionization method for mass spectrometry (MS). Laser light in the UV range is used to ionize molecules in a resonance-enhanced multiphoton ionization (REMPI) process. It is a selective and sensitive ionization method for aromatic and polyaromatic compounds. [Wikipedia]
A type of mass spectrometry where the sample is ionized by forcing a solution (usually in an organic solvent) of the sample through a small cold (10-80 °C) capillary (at a flow rate of 1-10 L min-1) into an electric field to produce a very fine mist of charged droplets. [CHMO]
matrix-assisted laser desorption ionization
Formation of gas-phase ions from molecules present in a solid or liquid matrix that is irradiated with a laser. The matrix is a material that absorbs the laser energy and promotes ionization. [IUPAC]
matrix-assisted laser desorption/ionization
A type of mass spectrometry where the sample is deposited on a solid surface known as an 'emitter' and ionized by interaction with a high electric field. [CHMO]
sonic spray ionization mass spectrometry
A type of mass spectrometry where ionization is achieved using a pneumatic nebuliser which turns the sample solution into a supersonic spray of small droplets. Ions are formed when the solvent evaporates and the statistically unbalanced charge distribution on the droplets leads to a net charge. [CHMO]
Mass spectrometry measurement that uses a semi-permeable membrane separator that permits the passage of analytes directly from solutions or ambient air to the mass spectrometer ion source. [IUPAC]
A type of mass spectrometry where a pressurised solution of the sample is forced through a heated metal capillary tip. Ions are formed when the solvent evaporates and the statistically unbalanced charge distribution on the droplets leads to a net charge. [CHMO]
Matrix-assisted laser desorption ionization in which the sample target is at atmospheric pressure and the ions formed by the pulsed laser are sampled through a small aperture into the mass spectrometer. [PSI-MS]
atmospheric pressure matrix-assisted laser desorption/ionization
J. M. Dyke, A. M. Shaw, T. G. Wright. J. Phys. Chem. 98, 6327 (1994).
Ionization of an atom or molecule by interaction with another internally excited atom or molecule. [IUPAC]
Chemi-ionization differs from Penning ionization in that chemical change is not excluded. [IUPAC]
This term is not synonymous with chemical ionization. [IUPAC]
A technique where analyte molecules are desolvated before they enter an EI or CI source. [Allotrope]
Technique used to investigate details of the collisional excitation process by studying trends relating scattering angle of the precursor ion, internal energy transferred, and the masses of the ion and its collision partner. [IUPAC]
Soft ionization alternative to matrix-assisted desorption/ionization involving laser desorption ionization of a sample deposited on a porous silicon surface. [IUPAC]
Multiple-stage mass spectrometry experiment with three or more stages of m/z separation in which products of sequential fragmentation or bimolecular reactions are selected for detection. [IUPAC]
Phenomenon in which the ionization efficiency of a compound is increased by the presence of another compound. [IUPAC]
The effect is most significant in electrospray ionization but is also observed in atmospheric pressure chemical ionization and to a lesser extent in other ionization methods. [IUPAC]
Ionization process that produces charged droplets and gas-phase ions from a liquid under vacuum with the application of an electric field. [IUPAC]
The process is formally equivalent to sub-ambient pressure electrospray ionization. [IUPAC]
Removal of solvent molecules clustered around a gas-phase ion by means of heating and/or collisions with gas molecules. [IUPAC]
The application of the accelerating voltage pulse after a time delay in desorption ionization from a surface. The extraction delay can produce energy focusing in a time-of-flight mass spectrometer. [PSI-MS]
X. Czeszak, W. Morelle, G. Ricart, D. Tétaert, J. Lemoine. Anal. Chem. 76, 4320 (2004).
Chemical derivatization of molecules to introduce a fixed charge site, thus improving ionization efficiency by electrospray ionization or matrix-assisted laser desorption/ionization and directing subsequent ion fragmentation in a manner that facilitates structure identification. [IUPAC]
Formation of ions in a corona discharge. [IUPAC]
Formation of gas-phase ions by chemical ionization of gaseous molecules produced by the rapid heating and desorption of a solid or low vapour pressure liquid. [IUPAC]
Ionization of a gas-phase atom or molecule by attachment of a free electron to form molecular ions of the M–• type. [IUPAC]
Mass spectrometry technique in which m/z values are represented by frequencies of ion motion and mass spectra are generated by Fourier transform mathematical operations from time domain transients produced by image current detection. [IUPAC]
Variant of matrix-assisted laser desorption/ionization in which the analyte is dissolved in a liquid matrix that is continuously supplied to the sample probe tip. [IUPAC]
continuous-flow matrix-assisted laser desorption/ionization
Scan in a tandem mass spectrometer with two or more m/z analyzers or in a sector mass spectrometer that incorporates at least one magnetic sector and one electric sector. The analyzers and/or other electric fields are scanned simultaneously so as to preserve a predetermined relationship between scan parameters to produce a product ion spectrum, precursor ion spectrum, constant neutral loss spectrum, or constant neutral mass gain spectrum. [IUPAC]
Partial random mixing of isotopes among specified atom positions in an ion or neutral species. [IUPAC]
In mass spectrometry, this term usually refers to the partial random mixing of isotopes in isolated ions that were formed with a fixed isotopic composition. [IUPAC]
Complete random mixing of isotopes between specified positions in an ion or neutral to achieve an equilibrium distribution of isotopes. [IUPAC]
In mass spectrometry, this term usually refers to the random mixing of isotopes in isolated ions that were formed with a fixed isotopic composition. [IUPAC]
Unstable trajectories in an ion trap for ions within a particular range of m/z values caused by an appropriate combination of oscillating electric fields. [IUPAC]
Peak matching is a mass analysis measuring the accurate mass of an ion using scanning mass spectrometers, in which the peak corresponding to the unknown ion and that for a reference ion of known m/z are displayed alternately and caused to overlap by adjusting appropriate electric fields. [IUPAC]
Method used to extend the amount of time available for mass spectrometric analysis of the components in a narrow chromatographic peak. The eluent flow rate is reduced to an ultra-low level at the leading edge of the peak and held at this low flow rate for the duration of compound elution, thus enabling collection of sufficient data for reliable statistical analysis. [IUPAC]
Electrospray ionization in which the axis of the spray is at a right angle to the axis of the sampling cone. [IUPAC]
Slow rotation of the center of cyclotron motion around the central axis of a Penning ion trap that results from a drift of the cyclotron centre along the electric equipotential lines perpendicular to the magnetic field direction. [IUPAC]
Means of determining m/z values of ions from experimentally detected signals using a theoretical or empirical relational equation. [IUPAC]
Most commonly this is accomplished using a computer-based data system and a calibration file obtained from a mass spectrum of a compound that produces ions of known m/z values. [IUPAC]
Data analysis technique used in elemental mass spectrometry to correct the intensity of an unresolved multiplet peak monitored for a specific element for contributions from a multi-isotopic contaminant.The correction is calculated from the measured intensity of a different isotopic peak of the contaminant and the known natural isotopic abundance ratio. [IUPAC]
Method of producing a mass spectrum from a mono-energetic ion beam by varying the strength of the magnetic field in a sector mass spectrometer. [IUPAC]
A sector magnetic field produces a momentum/charge spectrum of an ion beam, but if all ions have the same translational energy this is equivalent to a mass spectrum. The force F on a particle with charge q and velocity ν is F = q(ν × B). [IUPAC]
The magnetic field scan is sometimes called B-scan, but this is a misnomer since the symbol B denotes the magnetic flux density. The magnetic field strength H in a vacuum is defined in SI units as H = (1/μ0) B −M where μ0 is the magnetic constant or permeability of the vacuum and M the magnetization. B is often wrongly referred to as “magnetic field strength.�? [IUPAC]
Deflection of an ion beam as a result of the motion of the ions in a magnetic field. [IUPAC]
Generally, the direction of deflection of the ions is perpendicular to both the direction of the magnetic field and to that of the ion beam. [IUPAC]
Formation of ions through the interaction of photons from a laser with solid or liquid materials or with gas-phase atoms or molecules. [IUPAC]
Method for the determination of ion thermodynamic quantities by a procedure in which the relative probabilities of competing ionic dissociations are measured via the relative abundances of the reaction products. [IUPAC]
The extended kinetic method takes the associated entropy changes into account. [IUPAC]
Pulsed acceleration of ions perpendicular to their original direction of travel into a mass spectrometer, typically time-of-flight. [IUPAC]
Ions may be extracted from a directional ion source, drift tube, or m/z separation stage. [IUPAC]
Formation of gas-phase species from a solid or liquid sample surface upon activation using a short pulse of photons from a laser. [IUPAC]
Use of mass selective instability to eject ions of selected m/z values from an ion trap along the trap axis. [IUPAC]
Tandem mass spectrometry procedure in which product ion spectra are recorded for ion beams in m/z analyzers separated in space. Specific m/z separation functions are designed so that in one section of the instrument ions are selected, dissociated in an intermediate region, and the product ions are then transmitted to another analyzer for m/z separation and data acquisition. [IUPAC]
Process in which both anions and cations are produced at atmospheric pressure from an ionic solution due to a statistically unbalanced charge distribution in the minute droplets formed by the action of a sonic atomizer. [IUPAC]
C. L. Hendrickson, D. A. Laude. Anal. Chem. 67, 1717 (1995).
J. A. Marto, S. Guan, A. G. Marshall. Rapid Commun. Mass Spectrom. 8, 615 (1994).
Technique used in Fourier-transform ion cyclotron resonance mass spectrometers to limit the translational motion of the trapped ions so that they occupy a small volume near the trap center, thus optimizing performance criteria including resolving power. [IUPAC]
R. E. March, A. W. McMahon, E. T. Allinson, F. A. Londry, R. L. Alfred, J. F. J. Todd, F. Vedel. Int. J. Mass Spectrom. Ion Processes 99, 109 (1990).
Ejection of an ion from an ion trap in a direction perpendicular to the longitudinal axis of the trap. [IUPAC]
Tandem mass spectrometry procedure in which product ion spectra are recorded in a single m/z analyzer (such as a Paul ion trap, linear ion trap, or Fourier transform-ion cyclotron resonance-mass spectrometer) in discrete steps over time. Ions in a specific m/z range are selected, dissociated, and the product ions analyzed sequentially in time. [IUPAC]
Mass spectrometers that can perform tandem mass spectrometry in time can also perform MSn. [IUPAC]
Technique for axialization in Fourier transform-ion cyclotron resonance-mass spectrometers in which magnetron motion is converted into cyclotron motion by subjecting the trapped ions to a quadrupolar excitation field while they undergo collisions. [IUPAC]
Process whereby a precursor ion of a particular m/z is selected by m/z, fragmentation is induced, and the mass spectrum of the resulting product ions is recorded. [IUPAC]
Chemical ionization of an analyte where the reagent ion is an ionized form of the analyte or one of its product ions. [IUPAC]
Technique for the ejection of ions from an ion trap. [Allotrope]
Method of secondary ion mass spectrometry using low current densities for analysis of sample surface components, in contrast with dynamic secondary ion mass spectrometry. which is used for analysis of components in the depth direction. [IUPAC]
When the sample is an organic molecule in solid form the term is often changed to organic SIMS or molecular SIMS. [IUPAC]
Mode of ion ejection in an ion trap that relies on an auxiliary radio frequency potential that is applied to the end-cap or trapping electrodes. The potential is tuned to the classical oscillation frequency of a particular ion to eject it. [IUPAC]
Ejection of an ion from an ion trap in a direction parallel to the longitudinal axis of the trap. [IUPAC]
G. C. Thorne, K. D. Ballard, S. J. Gaskell. J. Am. Soc. Mass Spectrom. 1, 249 (1990)
G. Glish. J. Am. Soc. Mass Spectrom. 2, 349 (1991).
Mass spectrum recorded from any mass spectrometer in which the appropriate scan function can be set to record the appropriate generation product ion or ions of m/z selected precursor ions. [IUPAC]
nth generation product ion mass spectrum
Mass spectrum observed when no analyte is introduced into the mass spectrometer. [IUPAC]
Spectrum generated from MSn experiment with three or more stages of m/z separation and in which a particular multi-step reaction path is monitored. [PSI-MS]
Spectrum of all precursor ions that have undergone a selected m/z decrement corresponding to the mass of a particular neutral divided by the charge number of the precursor. The ions detected are the product ions produced by loss of a preselected neutral mass following collision-induced dissociation of the precursor ions in a collision cell. [IUPAC]
A high resolution mass spectrum is a type of mass spectrum that results from a high resolution mass spectrometer. [Allotrope]
Localized region of relatively intense detector response in a mass spectrum when ions of a specified m/z are detected. If resolving power is insufficient two or more components of similar m/z may contribute to one unresolved mass peak. [IUPAC]
Although mass peaks are often associated with particular ions, the terms peak and ion should not be used interchangeably. [IUPAC]
Care should be used to distinguish mass spectrum peaks from chromatographic peaks in GC-MS and LC-MS. [IUPAC]
Spectrum obtained when data are acquired from specific product ions corresponding to m/z values of selected precursor ions a recorded via two or more stages of mass spectrometry. The precursor/product ion pair is called a transition pair. Data can be obtained for a single transition pair or multiple transition pairs. Multiple time segments of different transition pairs can exist in a single file. Single precursor ions can have multiple product ions consitituting multiple transition pairs. Selected reaction monitoring can be performed as tandem mass spectrometry in time or tandem mass spectrometry in space. [PSI-MS]
MS1 spectrum that is enriched in multiply-charged ions compared to singly-charged ions. [PSI-MS]
Spectrum formed of all precursor ions that have undergone a selected m/z increase corresponding to the mass of a particular neutral species divided by the charge number of the precursor. The ions detected are the product ions produced by gain of a preselected neutral species mass following ion/molecule reactions of the precursor ions with a reactant gas in a collision cell. [IUPAC]
Plot of the relative abundances of ions that result from a charge inversion reaction as a function of m/z. [IUPAC]
A plot of relative abundance (%) vs. mass-to-charge ratio obtained from a mass spectrometry experiment where the ions are obtained by forcing a solution (usually in an organic solvent) of the sample through a small heated capillary (at a flow rate of 1-10 L min-1) into an electric field to produce a very fine mist of charged droplets. [CHMO]
A zoom scan is a plot of the charge distribution of a selected m/z range. [Allotrope]
B. N. Colby. J. Am. Soc. Mass Spectrom. 3, 558 (1992).
H. S. Gadgil, G. D. Pipes, T. M. Dillon, M. J. Treuheit, P. V. Bondarenko. J. Am. Soc. Mass Spectrom. 17, 867 (2006).
Mass spectrum processed with an algorithm designed to extract a desired signal or signals from raw experimental data in which the desired signals have been complicated (convolved) by some interferences or in some other way. [IUPAC]
Examples of deconvoluted mass spectra include mass spectra corrected for instrumental mass bias, or extraction of spectra for pure components from the spectrum of a mixture, or a mass (not m/z) spectrum of a biopolymer from an electrospray ionization spectrum containing peaks corresponding to several charge states. [IUPAC]
A mass spectrum obtained using a sector mass spectrometer in which the electric sector field E is set to half the value required to transmit the main ion-beam. This spectrum records the signal from doubly charged product ions of charge-stripping reactions. [PSI-MS]
The description of the specific part a chemical moeity that is assigned to a mass spectrum peak. [Allotrope]
A plot of relative abundance (%) vs. mass-to-charge ratio obtained from a mass spectrometry experiment where the sample is ionised by electrons (energy 70 eV) which have been emitted from a glowing filament and accelerated through an electric field. [CHMO]
multiple-stage mass spectrometry spectrum
Mass spectrum created by a multi-stage MS/MS experiments. [Allotrope]
Mass spectrum with peaks recorded in the absence of sample and due either to small air leaks or to the presence of molecules desorbed from the walls of the introduction device, the ion source, or from vacuum pump fluids. [IUPAC]
A mass spectrum of positive ions. [Allotrope]
A low resolution mass spectrum is a type of mass spectrum that results from a mass spectrometer working at low resolution. [Allotrope]
Mass spectrum in which the appropriate m/z separation analysis function is set to record the product ions of a selected precursor ion selected by m/z. [IUPAC]
A plot of relative abundance (%) vs. mass-to-charge ratio obtained from a mass spectrometry experiment where the ions are obtained by vaporization and ionization using a high-energy pulsed laser. [CHMO]
laser desorption-ionization mass spectrum
A mass spectrum of negative ions. [Allotrope]
MSn spectrum in which the product ions are collected after a time delay, which allows the observation of lower energy fragmentation processes after precursor ion activation. [PSI-MS]
A plot of relative abundance (%) vs. mass-to-charge ratio obtained from a mass spectrometry experiment where the ions are obtained by the sample interacting with reagent (N2, O2, H2O) gaseous ions at low pressure. [CHMO]
Graphical representation expressed in terms of dimensionless reduced coordinates that describes the stability or instability of charged particle motion in a transmission quadrupole mass spectrometer or Paul ion trap, based on an appropriate form of the Mathieu differential equation. [IUPAC]
Mass spectrum in which the appropriate m/z separation function records the precursor ions of selected product ions or specified neutral loss. [IUPAC]
Mass spectrum created by a single-stage MS experiment or the first stage of a multi-stage experiment. [PSI-MS]
A full scan mass spectrum is based on the data collected in the full scan mode, that is to say a target range of mass fragments is fully determined. [Allotrope]
Mass spectrum containing only ions made up of the principal isotopes of atoms of the original molecules. [IUPAC]
Spectrum obtained when a beam of ions is separated according to the translational energy-to-charge ratios of the ions contained in it. [IUPAC]
A radial electric field (E) achieves separation of the various ionic species in this way. [IUPAC]
In this context, kinetic energy is interpreted as translational, rather than vibrational or rotational kinetic energy. [IUPAC]
Ionization efficiency as a function of the energy of the electrons or photons used to produce ionization of a fixed number of molecules. [IUPAC]
Set of peaks related to ions with the same chemical formula but containing different isotopes that has a particular pattern associated with the relative abundance of the isotopes. [IUPAC]
Spectrum obtained when data are acquired that determine the m/z values of product ions produced by the reaction of a selected precursor ion with a user-specified m/z value. [IUPAC]
Diagram illustrating the relative contributions in unimolecular dissociation of an ion, for example, by homolytic cleavage of a single bond, and fragmentation following rearrangement. The diagram is in two parts with a common horizontal axis representing the internal energy of the ion. The vertical axis in one part of the diagram shows the two types of rate constant on a logarithmic scale, and that for the other portion of the diagram indicates the distribution function for internal energy of the ion. [IUPAC]
Mass in mass specrometry is a facet that describes the mass of a molecular entity. It can refer to different physical quantities depending on the characteristics of the instrument and the manner in which the mass spectrum is displayed. [Wikipedia]
The sprayer is continuously fed with sample. [PSI-MS]
The sprayer is loaded with sample once. [PSI-MS]
Double-focusing mass spectrometer configuration in which the ion beam traverses the magnetic sector prior to the electric sector. [IUPAC]
Double-focusing mass spectrometer configuration in which the ion beam traverses the electric sector before the magnetic sector. [IUPAC]
Arrangement for a double-focusing mass spectrometer in which a deflection of π/2 rad in a radial electro static energy analyzer is combined with a magnetic deflection of π/3 rad, thus providing a single point of focus for ions of the same m/z but with spreads in both trajectory direction and translational energy. [IUPAC]
Arrangement for a double-focusing mass spectrograph in which a deflection of π/(4√2) rad in a radial electrostatic energy analyzer is followed by a magnetic deflection of π/2 rad. [IUPAC]
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