Acronyms in Mass Spectrometry

May 1, 2006
Special Issues

Volume 0, Issue 0

The list of acronyms in mass spectrometry published regularly here reflects the writings and conversations of mass spectrometrists, who use a variety of acronyms to describe particular experiments or applications. New applications, with new audiences, bring new technical jargon.

The list of acronyms in mass spectrometry published regularly here reflects the writings and conversations of mass spectrometrists, who use a variety of acronyms to describe particular experiments or applications. New applications, with new audiences, bring new technical jargon. Shorthand-speak becomes common, and practitioners in one subdiscipline become more isolated, even in conversation, from their colleagues in other areas. This isolation is magnified by a dynamic lexicon that is as complex as it is specialized. Instruments are described by acronyms, along with ionization methods, analysis methods, experimental protocols, and data interpretation and presentation schemes. An environmental mass spectrometrist assesses results from an SIM GC–MS BTEX analysis. A carbohydrate mass spectrometrist works with data from PSD MALDI TOF using DHB matrices. Proteomics folks debate MOWSE scores from high-throughput PMF, all part of an NDA. To each group, these terms reflect their own ROOMS. Researchers enjoy coining acronyms as much as the federal government, and our acronym-laden language can be equally intimidating. This compilation may aid in our translations, both to others as well as for ourselves.

Some acronyms are protected trademarks but might not be noted as such in the literature. Companies coin acronyms, words, and descriptive phrases with the same gleeful abandon as individual researchers. I have not included vendor-specific acronyms or trademarks unless they seem to have entered common use. I also have resisted the inclusion of terms that only appear to be acronyms, but which are either unduly contorted or capitalized for the sake of appearance. Inclusion of an acronym in this list is not an explicit endorsement of its use by the community; the nomenclators eventually make their judgments, but the community itself enforces a certain discipline. Immortality in the annals of science is not to be gained by coining a new acronym; a truly useful acronym quickly becomes so widely used that the originator often is forgotten. Our search for fame (not FAME) then, leaves us only with eponomy, a topic that has merited specific academic study, although not yet in the field of mass spectrometry. Lastly, do not confuse an acronym with a shorthand for a chemical formula, or shorthand for a structure. Acronyms that appear in reference titles cannot be deciphered in context, and so will appear in this compilation.

For some recent additions to the acronym list, a short description is provided, along with a recent (not necessarily the first) reference. These vignettes should encourage you to visit the reference given for a more complete description. Acronyms are listed here in alphabetical order. Most acronyms are composed of upper-case letters, but a few are traditionally given as sequences of lower-case letters, or a mixture, to the consternation of spell checkers, editors, and indexers everywhere. The debate between GC–MS and GC/MS was settled long ago, but the community today doesn't seem to remember how or why the decision was made. I resist the urge to revisit the arguments. If your favorite acronym or abbreviation is missing from the list, please contact me.

A Anion

ACMS Asilomar Conference on Mass Spectrometry

ADC Analog-to-digital converter

ADO Average dipole orientation

AE Appearance energy

AEI Associated Electric Industries, a past MS manufacturer

AGC Automatic gain control

AGHIS All-glass-heated-inlet system

AMS Accelerator mass spectrometry; Adolescent mass spectrometrists

amu atomic mass unit

AN Auger neutralization; Application note (in JASMS)

ANP 2-Amino-5-nitropyridine (a MALDI matrix)

ANZSMS Australia and New Zealand Society for Mass Spectrometry

AP Appearance potential; Atmospheric pressure

APCI Atmospheric pressure chemical ionization

API Atmospheric pressure ionization

APPI Atmospheric-pressure photoionization

ARMS Angle-resolved mass spectrometry

ASGDIMS Atmospheric-sampling glow discharge ionization mass spectrometry

ASMS American Society for Mass Spectrometry

ASTM American Society for the Testing of Materials

ATT 6-Aza-2-thiothymine (a MALDI matrix)

AVS Accelerating voltage scan; American Vacuum Society

B Magnetic sector mass analyzer, magnetic field; magnetic sector field strength or flux density

BAMS Bioaerosol mass spectrometry

Individual cells of airborne Bacillus are differentiated based upon the reproducible spectral differences observed after laser ionization. Both positive and negative ion mass spectra are measured in the range to about 200 Da. Instrumental considerations for method development for real- time air monitoring are described. See: D.P. Fergenson, M.E. Pitesky, H.J. Tobias, P.T. Steele, G.A. Czerwieniec, S.C. Russell, C.B. Lebrilla, J.M. Horn, K.R. Coffee, A. Srivastava, S.P. Pillai, M.T.P. Shih, H.L. Hall, A.J. Ramponi, J.T. Chang, R.G. Langlois, P.L. Estacio, R.T. Hadley, M. Frank, and E.E. Gard, Anal. Chem. 76, 373–378 (2004).

BAT Best anode temperature

BDE Bond dissociation energy

B/E Linked scan for product ions in MS-MS

B2E Linked scan for parent ions in MS-MS

BEoQ A reverse-geometry sector instrument followed by an octupole collision cell followed by a quadrupole mass filter

BEqQ A reverse-geometry sector instrument followed by a collision quadrupole followed by a quadrupole mass filter

BEMS Biomedical and Environmental Mass Spectrometry (a former MS journal)

BET Best emitter temperature

BIAMS™ Biomolecular interaction analysis mass spectrometry

BIRD Blackbody infrared radiative dissociation

BMS Biomedical Mass Spectrometry, Biological Mass Spectrometry

BNG Bradbury–Nelson gate

The use of the Bradbury–Nelson gate as an ion modulation device and encoder for an ion beam is described in conjunction with its use in a Hadamard-transform time-of-flight mass spectrometer. See: O.K. Yoon, I.A. Zuleta, J R. Kimmel, M.D. Robbins, and R.N. Zare, J. Amer. Soc. Mass Spectrom.18, 1888–1901 (2005).

BTEX Benzene, toluene, ethylbenzene, and xylene

C Cation

CA Collisional activation

CAD Collisionally activated decomposition

CAF Chemically assisted fragmentation

CCA α-Cyano-4-hydroxycinnamic acid (a MALDI matrix)

CDEM Continuous-dynode electron multiplier

CDNT Conformation-dependent neutralization theory

Mass spectrometry now deals with high molecular mass, highly charged ions of complex structures. The reactions and structures of these ions is a matter of experimental interrogation as well as theoretical modeling. The authors discuss the CDNT theory in this paper and its applicability in determination of the charge state distribution for folded proteins in the gas phase. See: V.J. Nesatyy and M.J.-F. Suter, J. Mass Spectrom. 39, 93 (2004).

CE Charge exchange; Collision energy; Capillary electrophoresis

CEC Consolidated Electric Corporation (a former MS manufacturer)

CEMA Channel electron-multiplierarray

cf Conflat™

CFFAB Continuous-flow fast atom bombardment

CFP Continuous flow probe

CHCA Cyano-4-hydroxycinnamic acid (a MALDI matrix)

CI Chemical ionization

CID Collision-induced dissociation

CIDI Collisionally induced dissociative ionization

CIT Cylindrical ion trap

CM Center-of-mass

CMD Carbohydrate membrane desalter

CNL Constant neutral loss

CODA Component detection algorithm

COM Center-of-mass

COMSPARI Comparison of spectral retention information

CREMS Charge-reduction electrospray mass spectrometry

CRM Charged residue model

CS Charge stripping

CV Compensation voltage

CX Charge exchange

CXP Collision-cell exit potential

CZE–MS Capillary zone electrophoresis mass spec

D Disproportionation factor, Deuterium

Da Daltons

DA Dopant-assisted

DAC Digital-to-analog converter

DADI Direct analysis of daughter ions

DAPCI Desorption atmospheric pressure chemical ionization

DAR Data-acquisition routine

DART Direct analysis in real time

DB Database

dbe Double-bond equivalent

DCI Desorption (or direct) chemical ionization

DCT Double charge transfer

DCTB trans -2-[3-{4-tert-Butylphenyl}-2-methyl-2-propenylidene]malononitrile (a MALDI matrix)

DE Delayed extraction

DEI Desorption (or direct) electron ionization

DESI Desorption electrospray ionization

DESI is an ambient-pressure sampling method in which an electrospray ionization tip is used to generate charged droplets that impact a condensed phase surface that contains the sample. The vapors that leave the surface reflect the incident sample droplets as well as the surface composition of the condensed phase sample. The mechanisms of the total procss are complex, but two characteristics underscore the usefulness of the method: the high sensitivity of the subsequent mass spectrometric analysis and the ease with which a multitude of different samples can be accommodated. See: Z. Takáts, J.M. Wiseman, and R.G. Cooks, J. Mass Spectrom.40, 1261–1275 (2005).

DF Double focusing

DFTPP Decafluorotriphenylphos-phine

DHB 2,5-Dihydroxybenzoic acid (a MALDI matrix)

DI Desorption ionization

DIN Direct injection nebulizer

DIOSMS Desorption ionization on silicon mass spectrometry

DIP Direct-insertion probe

DLI Direct liquid introduction

DLV Direct laser vaporization

DNFW Latin for "Please do not mess with the instrument"

DP Direct probe; Declustering potential; Diffusion pump

DPBD Diphenyl butadiene (a MALDI matrix)

DS Data system

DTIMS Drift-tube ion mobility spec

E Energy; Electric sector

EA Electron affinity

EAD Electron avalanche desorption

ECD Electron-capture dissociation

ECID Electron-capture-induced dissociation

ECMS Electron-capture mass spec

ECNCI Electron-capture negative chemical ionization

ECNI Electron-capture negative ionization

ECP Emitter-current programmer

EDD Energy-distribution difference

EE Even-electron ion

EED Electron excitation dissociation

EHI Electrohydrodynamic ionization

EI Electron ionization, Electron impact

EIEIO Electron-induced excitation of ions from organics

EIS External ion source

EJMSEuropean Journal of Mass Spectrometry

EM Electron multiplier

EMP Electron multiplier

EOID Electrooptical ion detector

EP Entrance potential

ERMS Energy-resolved mass spectrometry

ES Electrospray; Electrospray ionization

ESA Electrostatic analyzer

ESCI Combined electrospray and atmospheric pressure ionization source

ESI Electrospray ionization

ESP Electrospray ionization

ESPI Electrospray ionization

esu Electrostatic unit

ET Electron transfer

ETD Electron-transfer dissociation

Electron-capture dissociation has proven useful in the sequence analysis of peptide ions stored in a Fourier-transform instrument in which the peptide ions interact with a population of thermal electrons. However, a quadrupole ion trap, also a common instrument used for these analyses, will not store the thermal electrons. An anionic carrier is therefore used to transfer an electron in a low-energy collision with the positive peptide ions, and initiate the electron-induced nonergodic dissociation. See: J.E.P. Syka, J.J. Coon, M.J. Schroeder, J. Shabanowitz, and D.F. Hunt, Proc. Nat. Acad. Sci. USA 101, 9528–9533 (2004).

ETV Electrothermal vaporization

eV Electron volt

FA Flowing afterglow; Ferulic acid (a MALDI matrix)

FAB Fast-atom bombardment

FAIMS High Field Asymmetric Waveform Ion Mobility Spectrometry

FAME Fatty acid methyl ester

FC Faraday cup

FD Field desorption

FFID Fission-fragment-induced desorption

FFR Field-free region

FI Field ionization

FIA Flow-injection analysis

FIB Fast-ion bombardment

FIK Field ionization kinetics

FIMS Field-ionization mass spectrometry

FNB Fast-neutral beam

FRET Fluorescence resonance energy transfer

FRET is the study of changes in measured fluorescence intensity from molecules as a function of their three-dimensional conformation. It has been used to study conformations in the cellular condensed phase, and more recently for gas phase ions in an FTMS system. These ions have been tagged with the appropriate donors, acceptors, and quenchers, and the changes in fluorescence used as a molecular ruler. See: M. Dashtiev, V. Azov, V. Frankevich, L. Scharfenberg, and R. Zenobi, J. Amer. Soc. Mass Spectrom.16, 1481–1497 (2005).

FTICR Fourier transform ion cyclotron resonance

FTMS Fourier transform mass spectrometry

FT-TOF Fourier transform-time-of-flight mass spectrometry

FWHH Full width at half height

FWHM Full width at half maximum

G Multiplier gain; Glycerol (an LSIMS matrix)

GC Gas chromatography

GC–MS Gas chromatography–mass spectrometry

GDMS Glow discharge mass spectrometry

GIANT Gas-phase ion and neutral thermochemistry (a published compilation of such data)

GLP Good laboratory practice

GPC Gel permeation chromatography

HABA 2-(4-Hydroxyphenylazo) benzoic acid (a MALDI matrix)

HASTE High-amplitude short-time excitation

The operation of a quadrupole ion trap mass spectrometer for MS-MS requires that ions be excited by collision with a neutral target gas so that dissociation occurs, but that all of the ions so formed be retained within the trap so that the resultant mass spectrum can be accurately measured. The discordant goals of excitation and trapping are compromised in the usual electronic operation of an ion trap, with a longer excitation leading to loss of lower-mass ions in the MS-MS spectrum. Recent work involves the use of a higher amplitude and shorter duration excitation function. Extra credit goes to an acronym with a true mnemonic significance. See: C. Cunningham, Jr., G.L. Glish, and D.J. Burinsky, J. Amer. Soc. Mass Spectrom. 17, 81–84 (2006).

4-HBSA 4-Hydroxybenzenesulfonic acid (an LSIMS matrix)

HCCA α-Cyano-4-hydroxycinnamic acid (a MALDI matrix)

HCD Heated capillary dissociation

HCP Hollow cathode plume

H/D Hydrogen/deuterium

HDX Hydrogen/deuterium exchange

HE High energy

HECD Hot electron capture dissociation

2-HEDS 2-Hydroxyethyl disulfide (an LSIMS matrix)

HMM High molecular mass

HPA 3-Hydroxypicolinic acid (a MALDI matrix)

2-HEPA 2-Hydroxyphenethyl alcohol (an LSIMS matrix)

HPMS High-pressure mass spectrometer

HRMS High-resolution mass spectrometry

HSI Hyperthermal surface ionization

HSMS Headspace mass spec

HT Hadamard transform; High tension, which is a Britishism for HV (high voltage)

HTMS High temperature mass spectrometry

HT-TOF-MS Hadamard-transform time-of-flight mass spectrometry

HV High voltage

HXMS Hydrogen/deuterium exchange mass spectrometry

IAA Indole acrylic acid (a MALDI matrix)

IC Ion chromatography

ICAT Isotope-coded affinity tag

ICDR Ion cyclotron double resonance

ICEMS Ion-pair liquid chromatography electrospray ionization mass spectrometry

IC–MS Ion chromatography–mass spectrometry

ICP–MS Inductively coupled plasma-mass spectrometry

ICR Ion cyclotron resonance

IDMS Isotope dilution mass spectrometry

IE Ionization energy; Ionizing energy; Ion evaporation

IELC Ion exchange liquid chromatography

IJMSIP International Journal of Mass Spectrometry and Ion Physics (Volumes 1–62)

International Journal of Mass Spectrometry and Ion Processes (after Volume 62)

IJMS International Journal of Mass Spectrometry

IKE(S) Ion kinetic energy (spectrometry)

IMAC Immobilized metal affinity chromatography

IP Ionization potential

IPD Ion-photon detector

IRMPD Infrared multiphoton dissociation

IRMPD in MALDI was used in conjunction with CID and ESI, along with HDX studies and computational simulations (illustrating the power of acronym-shorthand), to study the gas-phase fragmentation of 2-hydroxybenzyl-N-pyridinylamine derivatives. The comprehensive work allowed a comparison to both the classical solution mechanism as well as the proposed unique gas-phase fragmentation. See: H.-Y. Wang, X. Zhang, Y.-L. Guo, and L. Lu, J. Am. Soc. Mass Spectrom.16, 1561–1573 (2005).

IRMS Isotope ratio mass spectrometry

ISD In-source decay

ISP Ionspray

ISR Ion/surface reaction

ITD™ Ion trap detector

ITMS Ion trap mass spectrometry

ITPMS Isotacophoresis mass spectrometry

IUPAC International Union of Pure and Applied Chemistry

JASMS Journal of the American Society for Mass Spectrometry

JEOL Japan Electro-Optics Laboratory

JMS Journal of Mass Spectrometry

K Kelvin

KCMS Knudsen cell mass spectrometry

kDa Kilodalton

KERD Kinetic energy release distribution

K+IDS Potassium ion desorption spectrometry

KM Kinetic method

KNN K-nearest neighbor

L Length of flight tube

LAMMA™ Laser microprobe mass analyzer

LAMPAS Laser mass analyzer for particles in the airborne state

LBO Light beam oscillograph

LC–MS Liquid chromatography –mass spectrometry

LD Laser desorption

LDI Laser desorption ionization

LDLP Laser desorption/laser photoionization

LE Low energy

LI Liquid ionization

LIMA™ Laser ionization mass analyzer; Laser ion microprobe analyzer

LIT Linear ion trap

LMCO Low mass cut-off

LMM Low molecular mass

LMMS Laser microprobe mass spectrometer

LMS Laser mass spectrometry

LMW Low molecular weight

LOD Limit of detection

Look here for an excellent overview of establishing the fitness for purpose of mass spectrometric methods. This publication includes essential definitions and discussions of analytically important terms such as the limit of detection. See: R. Bethem, J. Boison, J. Gale, D. Heller, S. Lehotay, J. Loo, S. Musser, P. Price, and S. Stein, J. Am. Soc. Mass Spectrom. 14(5), 528 (2003).

LOQ Limit of quantification

LRB Laboratory reagent blank

LSIMS Liquid matrix secondary ion mass spectrometry

LTOF Laser time-of-flight; Linear time-of-flight

LV/EI Low voltage electron ionization

m Mass of the ion in units of u

M/A Matrix/analyte ratio

Matrix-assisted laser desorption ionization mass spectrometry is dependent upon the admixture of sample with an energy-absorbing matrix. The existence of the matrix effect is central, and studies of how it is manifest are particular interesting. In this publication, the effect of changing matrix-to-analyte ratios on the mass distribution of ions in a standard polymeric mixture is explored. See: A.J. Jaber, J. Kaufman, R. Liyanage, E. Akhemotova, A. Marney, and C.L. Wilkins, J. Am. Soc. Mass Spectrom. 16, 1772–1780 (2005).

MAGIC Monodisperse aerosol generator interface to chromatography

MALD Matrix-assisted laser desorption

MALDI Matrix-assisted laser desorption ionization

MAPS Method for analyzing patterns in spectra

MB Molecular beam

MBMS Molecular beam mass spectrometry

MCA Multichannel analyzer

MCI Massive cluster impact

MCMS Midwest Center for Mass Spectrometry

MCP Microchannel plate (detector)

MCPD Microchannel plate detector

MEND Matched filtration with experimental noise determination

MDMS Microdialysis mass spectrometry

MDL Method detection limit

MESIMS Matrix-enhanced secondary ion mass spec

Hanton and Owens report research using some common MALDI matrices for preparation of polymer samples analyzed by secondary ion mass spectrometry, using polmers in the mass distribution range of 1000–4000 Da to record MESIMS spectra and compare them to MALDI mass spectra. The concept of matrix-assisted SIMS precedes MALDI, dating to the early 1980s. See: S.D. Hanton and K.G. Owens. J. Am. Soc. Mass Spectrom. 16, 1172–1180 (2005).

MI Metastable ion

MID Multiple ion detection

MIKE(S) Mass-analyzed ion kinetic energy (spectrometry)

MIM Multiple ion monitoring

MIMS Membrane introduction mass spectrometry

MIP Microwave-induced plasma

MNBA meta-Nitrobenzyl alcohol, an LSIMS matrix

MNDO Modified neglect of differential overlap

MO Molecular orbital

MOWSE Molecular weight search

One of the first publications that described this program appeared in 1993. This work showed that proteins can be identified uniquely by match of as few as three accurately determined masses for peptides when those masses are found in a large database that contains accurate masses and proteins that give rise to them. As the number of possibilities rise, so does the need for additional accurate masses; the relationship is a classic study in bioinformatics. See: D.J.C. Pappin, P. Hojrup, and A.J. Bleasby, Curr. Biol. 3(6), 327–332 (1993).

MPD Multiphoton dissociation

MPI Multiphoton ionization

MPM Multiple peak monitoring

MQDT Multichannel quantum defect theory

MRM Multiple reaction monitoring

MSn If n = 2, MS-MS. If n = 3, MS-MS-MS. Repeat as necessary.

MSB Mass Spectrometry Bulletin

MSD Mass-selective detector

MSDC Mass Spectrometry Data Center

MSM Multiple scattering method

MSR Mass Spectrometry Reviews

MS-MS Mass spectrometry-mass spec

MSSS Mass spectral search system

MULTUMMultiturn mass spectrometer

A multiturn time-of-flight mass spectrometer has been used to achieve high mass resolution for ions generated by MALDI by multiple passages of the ion through the flight tube. A sophisticated ion injection and timing scheme must be used to accomplish this feat, but the authors demonstrate feasibility and impressive results. See: D. Okumura, M. Toyoda, M. Ishihara, and I. Katakuse, J. Mass Spectrom. 39, 86 (2004).

MW Molecular weight

Mwt Molecular weight

m/z Mass-to-charge ratio

N Neutral molecule or species

NBA meta-Nitrobenzyl alcohol (an LSIMS matrix)

NCBI National Center for Biotechnology Information

NCE Normalized collision energy

NCI Negative ion chemical ionization

NET Normalized elution time

NI Negative ion

NICI Negative ion chemical ionization

NOBA meta-Nitrobenzyl alcohol (an LSIMS matrix)

+NR+ Neutralization reionization; a positive ion is neutralized and then reionized

NRMS Neutralization reionization mass spectrometry

NSI Nanospray ionization

o Orthogonal

oa Orthogonal acceleration

ODN Oligodeoxynucleotide

OE Odd-electron ion

OMS Organic Mass Spectrometry

oTOF Orthogonal (source) time-of-flight

PA Proton affinity

PAD Post-acceleration detector

PAI Post-ablation ionization

PALMS Particle analysis by laser mass spectrometry

PBM Probability-based matching

PBMS Particle-beam mass spectrometry

PCA Principal component analysis

PCI Positive ion chemicalionization

PCR Polymerase chain reaction

The polymerase chain reaction is used to amplify sequences, and the products are often later analyzed by a combination of chromatography and mass spectrometry. Commercial PCR products contain components that can ultimately affect the quality of the mass spectral data through complex matrix effects. Analytical results using different commercial products and some general guidelines for the analysis of genomic DNA are described in a recent publication. See: H. Oberarcher, H. Niederstätter, B. Casetta, and W. Parson, J. Am. Soc. Mass Spectrom. 17, 124–129 (2006).

PD Plasma desorption; Photodissociation

PDF Pulsed dynamic focusing

PDMS Plasma desorption mass spectrometry

PEPICO Photoelectron-photoion coincidence spectroscopy

PES Photoelectron spectroscopy

PFK Perfluorokerosene

PFTBA Perfluorotributylamine

PHD Pulse height distribution

PHT Peptide hits technique

PI Positive ion

PID Particle-induced desorption; Photon-induced dissociation

PIE Photoionization efficiency

PIT Protein-identification technology

PIT-MS Proton-transfer ion-trap mass spectrometry

PIPECO Photoion-photoelectron coincidence spectroscopy

PLE Pressurized liquid extraction

PMF Peptide mass fingerprinting

PMM Peptide mass maps

PMS Parallel mass spectrometry

PPINICI™ Pulsed positive ion negative ion chemical ionization

PSD Postsource decay

PSI Pulsed sample introduction

PSM Peptide–spectrum match

PSPF Postsource pulse focusing

PTM Post-translational modification

PTR Proton-transfer reaction

PyMS Pyrolysis mass spectrometry

q Quadrupole device used in rf-only mode as a collision cell

Q Quadrupole mass filter

Q Reaction endothermicity

QA Quality assurance

QC Quality control

qCID Collision-induced dissociation accomplished within an rf-only quadrupole

QCPE Quantum Chemistry Program Exchange

QET Quasi-equilibrium theory

QFTMS Quadrupole Fourier-transform mass spectrometry

QIT Quadrupole ion trap

QLT Quadrupole linear ion trap

QTOF Quadrupole followed by a time-of-flight mass analyzer

QUISTOR Quadrupole ion storage trap

r Radius of electric or magnetic sector

RA Relative abundance; all-trans-retinoic acid (a MALDI matrix)

RCM Rapid Communications in Mass Spectrometry

rdbe Rings plus double bonds equivalent

REMPI Resonance-enhanced multiphoton ionization

RF Radio frequency; Response factors

RGA Residual gas analyzer

RI Relative intensity

RIMS Resonance-ionization mass spectrometry

RiT Rectilinear ion trap

Recent works examine boundary and resonance ejection phenomena in an RIT as a means to characterize higher order factors that affect the performance of the mass analyzer. See: Z. Ouyang, G.X. Wu, Y.S. Song, H.Y. Li, W.R. Plass, and R.G. Cooks, Anal. Chem. 76(16), 4595–4605 (2004); and A.M. Tabert, M.P. Goodwin, and R.G. Cooks, J. Am. Soc. Mass Spectrom.17, 56–59 (2004).

RLCT Rayleigh limiting charge theory

RN Resonance neutralization

ROOMS Regular old ordinary mass spectrometry (courtesy of R.A. Hites)

R2PI Resonant 2-photon ionization

RP Resolving power

RPD Retarding potential difference

RPLC Reversed-phase liquid chromatography

RRKM Rice, Ramsperger, Kassel, and Marcus

RSMS Rapid single particle mass spectrometer

rTOF Reflectron time-of-flight

SA Sinapinic acid (a MALDI matrix)

SCMSS Sanibel Conference on Mass Spectrometry

SCX Strong cation exchange

SDM Selected dissociation monitoring

SEAC Surface-enhanced affinity capture

SEC Size-exclusion chromatography

SELDI Surface-enhanced laser desorption ionization

SEND Surface-enhanced neat desorption

SFC-MS Supercritical fluid chromatography–mass spectrometry

SFE Supercritical fluid extraction

SI Spray ionization; Surface ionization

SID Surface-induced dissociation

SIFDT Selected-ion flow drift tube

SIFT Selected-ion flow tube

SILVER Spectrum intensity likelihood viewer

SILVER is a mass spectrum viewer program that displays the results of matching algorithms and probabilistic based scoring routines in such a way that facilitates a final decision by a person actually evaluating the data. See F.D. Gibbons, J.E. Elias, S.P. Gygi, and F.P. Roth, J. Am. Soc. Mass Spectrom. 15, 910–912 (2004).

SIM Selected-ion monitoring

SIMBROC Simulated background and reduction–oxidation calculations

SIMS Secondary ion mass spectrometry

SIN Surface-induced neutralization

SIOMS Surface ionization organic mass spectrometry

SIR Selected-ion recording

SMB Supersonic molecular beam

SMOKE Stored modulation of kinetic energy

SMOW Standard mean ocean water

S/N Signal-to-noise ratio

SOMO Singly occupied molecular orbital

SPE Solid-phase extraction

SPME Solid-phase micro extraction

SRBC Simulated reduction and background calculations

SRM Selected reaction monitoring; Standard reference material

SSIMS Static secondary-ion mass spectrometry

SSMS Spark source mass spec

STIRS Selftraining interpretive and retrieval system

STMT Stieltjes–Tchebycheff moment theory

SWIFT Stored-waveform inverse Fourier transform

SWIM Stored waveform ion modulation

t Ion flight time; Time

T Tesla

TAC Time-to-amplitude converter

TAMS Tandem accelerator mass spectrometry

TDC Time-to-digital converter

TEL Translational energy loss

TEPSICO Threshold electron photoion secondary ion coincidence

TES Translational energy spectroscopy

TGAMS Thermogravimetric analysis mass spectrometry

TG GC–MS Thermogravimetry gas chromatography–mass spectrometry

TI Thermal ionization

TIC Total ion current

TID Trapped-ion detector; Thermally-induced dissociation

TIMS Thermal-ionization mass spectrometry

TISI Turbo ion-spray ionization

TIP True isotopic pattern (trademark)

TLC-MS Thin layer chromatography–mass spectrometry

TMS Trimethylsilyl; Tandem mass spectrometry; Thermospray mass spectrometry

ToF Time-of-flight

TOF Time-of-flight

TOFMS Time-of-flight mass spectrometry

TQ Triple quadrupole

TQMS Triple-quadrupole mass spectrometry

TRPD Time-resolved photodissociation

TSP Thermospray

TSQ™ Triple stage quadrupole

u mass unit (1/12 of the mass of 12 C), now replaced by dalton

UVLD Ultraviolet laser desorption

UVPD Ultraviolet photodissociation

v ion velocity

V Accelerating voltage

VG Vacuum Generators, former name of a manufacturer of mass spectrometers

VOC Volatile organic compound

VTST Variational transition state theory

W Wien filter

z charge state of the ion in units of the electric charge

ZPE Zero-point energy