Acronyms in Mass Spectrometry

May 2, 2005
Kenneth L. Busch
Special Issues

Volume 0, Issue 0

Back by popular demand, Spectroscopy's resident MS expert, Ken Busch, presents a list of common acronyms used in the field.

We have previously published (Spectroscopy, 17[2], 54 [2002]) a list of common acronyms in mass spectrometry, reflecting the need for elucidation of shorthand terms used by mass spectrometrists to describe particular experiments or applications. It might be tempting to relegate the usefulness of such lists to newcomers, or to the uninitiated, but this is unwise for an analytical endeavor that expands and evolves as quickly as does mass spectrometry. As the field grows, the practitioners in one sub-discipline invariably become more isolated from their colleagues in another area of application. An environmental mass spectrometrist is comfortable with assessment of results from a SIM GC-MS BTEX analysis. A carbohydrate mass spectrometrist will feel more at home with data originating in a PSD MALDI TOF experiment using DHB; different folks like different ROOMS.

Most of the acronyms in this compilation find common use in the literature and at professional meetings. Some acronyms in common use are protected trademarks (past, present, or future), and precautions should be exercised in their appearance in the literature. Inclusion of an acronym in this list is explicitly not an endorsement for its use, especially when there may be a "competitive" acronym available. Let the nomenclators make their judgments; in this compilation, errors will fall on the side of unabashed inclusion, and a few "symbols" will sneak in as well. Particular attention has been given to acronyms introduced to the field of mass spectrometry within the past few years. For recent additions to the acronym list, a short description is provided, along with a recent (and not necessarily the first) reference.

Acronyms are listed 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 in word processors everywhere. If your favorite acronym or abbreviation is missing from the list, please feel free to contact the author.

The contents of this article represent the views of the author and not those of the National Science Foundation (NSF). Contact Ken at: can be reached at: E-mail: .

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

amu atomic mass unit

AN Auger neutralization

ANP 2-amino-5-nitropyridine, a MALDI matrix

ANZSMS Australia and New Zealand Society for Mass Spectrometry

R. A. J. O'Hair, Eur. J. Mass Spectrom., 9(6), 525 (2003)

A brief historical vignette of ANZSMS is found in this article, along with perhaps the only musical selection published in a mass spectrometry journal. The location of perhaps the only poem published in a mass spectrometry journal shall remain the author's personal secret.

AP Appearance potential

APCI Atmospheric pressure chemical ionization

API Atmospheric pressure ionization

ARMS Angle-resolved mass spectrometry

ASGDIMS Atmospheric-sampling glow discharge ionization mass spectrometry

ASMS American Society for Mass Spectrometry

ASTM American Society for Testing and Materials

ATT 6-aza-2-thiothymine, a MALDI matrix

AVS Accelerating-voltage scan

American Vacuum Society

b impact parameter

B Magnetic sector mass analyzer, magnetic field

Magnetic sector field strength or flux density

BAT Best anode temperature

BDE Bond dissociation energy

P. Armentrou, Eur. J. Mass Spectrom., 9(6), 531 (2003)

The kinetic energy dependence of reactions between mass-selected ions and neutral molecules is interpreted to provide the threshold for the process, revealing basic thermochemical information such as the bond dissociation energy for intriguing metal-containing species.

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

D. Nedelkov and R. W. Nelson, J. Molec. Recogn., 16, 15 (2003)

In this combined technique, a surface plasmon resonance sensor first is used to characterize an analyte bound to an affinity labeled surface. Then, MALDI matrix is added, the analyte is desorbed and ionized, and the MALDI mass spectrum is used to characterize the surface species.

BIRD Blackbody infrared radiative dissociation

BMS Biomedical mass spectrometry, biological mass spectrometry

BTEX Benzene, toluene, ethylbenzene, and xylene

C Cation

CA Collisional activation

CAD Collisionally activated decomposition

CAF Chemically assisted fragmentation

CCA alpha-cyano-4-hydroxy cinnamic acid, a MALDI matrix

CDEM Continuous-dynode electron multiplier

CDNT Conformation-dependent neutralization theory

V. J. Nesatyy and M .J.-F. Suter, J. Mass Spectrom., 39, 93 (2004)

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.

CE Charge exchange

Capillary electrophoresis

CEC Consolidated Electric Corporation (a former MS manufacturer)

CEMA Channel electron-multiplier array

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

CNL Constant neutral loss

CODA Component detection algorithm

COM Center-of-mass

COMSPARI Comparison of spectral retention information

J. E. Katz, D. S. Dumlao, S. Clarke, and J. Hau, J. Amer. Soc. Mass Spectrom., 15(4), 580 (2004)

COMSPARI is a collection of data visualization software that allows the analyst to detect small differences in complex datasets, including GC-MS and LC-MS data. Perceptive differences in mirrored displays are key to highlighting spectral differences.

CREMS Charge-reduction electro-spray mass spectrometry

CS Charge stripping

CV Compensation voltage

CX Charge exchange

CZE-MS Capillary zone electrophoresis mass spectrometry

D Disproportionation factor


Da Daltons

DAC Digital-to-analog converter

DADI Direct analysis of daughter ions

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

DF Double focusing

DFTPP Decafluorotriphenylphosphine

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

DP Direct probe

Diffusion pump

DS Data system

DTIMS Drift-tube ion mobility spectrometry

E Energy, Electric sector mass analyzer

Electric sector voltage

EA Electron affinity

EAD Electron avalanche desorption

ECD Electron-capture dissociation

ECID Electron-capture-induced dissociation

ECMS Electron-capture mass spectrometry

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 (or 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 Electro-optical ion detector

ERMS Energy-resolved mass spectrometry

ES Electrospray or 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

ETV Electrothermal vaporization

eV electron volt

FA Flowing afterglow

FAB Fast atom bombardment

FAIMS High Field Asymmetric Waveform Ion Mobility Spectrometry

W. Gabryelski and K. L. Froese, J. Amer. Soc. Mass Spectrom., 14(3), 278 (2004)

Changes in ion mobility measured at a relatively high dispersion voltage are measured to separate various isomers as they move through a transport region and ultimately into a mass analyzer.

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

FT-ICR Fourier-transform ion cyclotron resonance

FT-MS Fourier-transform mass spectrometry

FT-TOF MS 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

4-HBSA 4-hydroxybenzenesulfonic acid, an LSIMS matrix

HCCA alpha-cyano-4-hydroxycinnamic acid, a MALDI matrix

HCD Heated capillary dissociation

HCP Hollow cathode plume

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-HPEA 2-Hydroxyphenethyl alcohol, an LSIMS matrix

HRMS High resolution mass spectrometry

HSI Hyperthermal surface ionization

HSMS Headspace mass spectrometry

HT High tension, which is a Briticism for high voltage

HTMS High temperature mass spectrometry

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

HXMS hydrogen/deuterium exchange mass spectrometry

A. Nazabal, M. Laguerre, J.-M. Schmitter, J. Vaillier, S. Chaignepain, and J. Velours, J. Amer. Soc. Mass Spectrom., 14(5), 471(2003)

Acidic hydrogens in accessible positions will exchange for deuteriums in the proper solvent. Mass spectrometry is used to "count" and sometimes locate the exchanged atoms, because the masses of ions recorded in the mass spectrum will differ. The experimental targets range from simple molecules to complex three-dimensional structures of peptides and proteins.

IC Ion chromatography

ICAT Isotope-coded affinity tag

ICDR Ion cyclotron double resonance

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

K. Hakansson, R. R. Hudgins, A. G. Marshall, and R. A. J. O'Hair, J. Amer. Soc. Mass Spectrom., 14(1), 23 (2003)

A comparison between ECD and IRMPD for oligodeoxynucleotide dications was completed with an FT-ICR instrument. Different means of mass-selected parent ion activation resulted in different dissociation processes, each with specific advantages in determining structure.

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

JMS Journal of Mass Spectrometry

K Kelvin

KCMS Knudsen cell mass spectrometry

M. Heyrman, C. Chatillon, H. Collas, and J. L. Chemin, Rapid Commun. Mass Spectrom., 18(2), 163 (2004)

A Knudsen cell is a high-temperature device that is used to create a vapor phase in thermal equilibrium with a condensed phase. Sampling of the vapor phase species by a mass spectrometer allows characterization of the various components that determine the overall thermal equilibrium.

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

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

LMM Low molecular mass

LMMS Laser microprobe mass spectrometer

LMS Laser mass spectrometry

LOD Limit of detection

R. Bethem, J. Boison, J. Gale, D. Heller, S. Lehotay, J. Loo, S. Musser, P. Price, and S. Stein, J. Amer. Soc. Mass Spectrom., 14(5) 528 (2003)

This reference is an excellent overview of establishing the fitness for purpose of mass spectrometric methods. It includes essential definitions and discussions of analytically important terms such as the limit of detection.

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

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

m mass of the ion in units of u

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

MCP Microchannel plate

MCPD Microchannel plate detector

MDMS Microdialysis mass spectrometry

MDL Method detection limit

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

MPD Multiphoton dissociation

MPI Multi-photon ionization

MPM Multiple peak monitoring

MQDT Multi-channel 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 spectrometry

MSSS Mass spectral search system

MULTUM Multiturn mass spectrometer

D. Okumura, M. Toyoda, M. Ishihara, and I. Katakuse, J. Mass Spectrom., 39, 86 (2004)

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.

MW Molecular weight

Mwt Molecular weight

N Neutral molecule or species

NBA meta-Nitrobenzyl alcohol, an LSIMS matrix

NCI Negative ion chemical ionization

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

o Orthogonal

oa Orthogonal acceleration

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

PBM Probability-based matching

PBMS Particle-beam mass spectrometry

PCI Positive ion chemical ionization

PD Plasma desorption


PDMS Plasma desorption mass spectrometry

PEPICO Photoelectron-photoion coincidence spectroscopy

PES Photoelectron spectroscopy

PFK Perfluorokerosene

PFTBA Perfluorotributylamine

PHD Pulse height distribution

PI Positive ion

PID Particle-induced desorption

Photon-induced dissociation

PIE Photoionization efficiency

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 Post-source decay

A. J. Hoteling and K. G. Owens, J. Amer. Soc. Mass Spectrom., 15(4), 523 (2004)

Post-source decay is a term often used in conjunction with a time-of-flight mass spectrometer. After the ions are formed in the source and accelerated into the analyzer region, they can unimolecular dissociate, or can be induced to dissociated through collision. Manipulation of subsequent focusing and reflecting voltages can elucidate these mass-changing reactions.

PSI Pulsed sample introduction

PSPF Post source pulse focusing

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

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

RCM Rapid Communications in Mass Spectrometry

rdbe Rings plus double bonds equivalent

REMPI Resonance-enhanced multi-photon ionization

rf Radio frequency

Response factors

RGA Residual gas analyzer

RI Relative intensity

RIMS Resonance-ionization mass spectrometry

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

rTOF Reflectron time-of-flight

SA Sinapinic acid, a MALDI matrix

SCMS Sanibel Conference on Mass Spectrometry

SDM Selected dissociation monitoring

SEAC Surface-enhanced affinity capture

SEC Size exclusion chromatography

SELDI Surface-enhanced laser desorption ionization

N. Tang, P. Tornatore, and S. R. Weinberger, Mass Spectrom. Rev., 23, 34 (2004)

In SELDI, the matrix that supports the sample of interest also serves to purify, extract, or modify the sample. More precisely, the SELDI matrix is designed for a particular target analyte, as contrasted with the general purpose matrices used in MALDI.

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

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

SNR Signal-to-noise ratio

SPE Solid phase extraction

SPME Solid phase micro extraction

SRBC Simulated reduction and background calculations

SRM Selected reaction monitoring

Standard reference material

SSMS Spark source mass spectrometry

STIRS Self-Training 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

Kinetic energy release value

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 hromatography-mass spectrometry

TI Thermal ionization

TIC Total ion current

TID Trapped ion detector

Thermally induced dissociation

TIMS Thermal ionization mass spectrometry

TISI Turbo ionspray ionization

TLC-MS Thin layer chromatography-mass spectrometry

TMS Trimethylsilyl, tetramethylsilane

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

uVLD Ultraviolet laser desorption

UVPD Ultraviolet photodissociation

v ion velocity

V Accelerating voltage

Accelerating voltage scan

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

VOC Volatile organic compound

VTST Variational transition state theory

W Wien filter

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