Differential mobility spectrometer: Model of operation

Krylov, Evgeny V.; Nazarov, Erkinjon G.; Miller, Raanan A.

doi:10.1016/j.ijms.2007.07.003

Cited by 160 publications

(202 citation statements)

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“…The mobility of any ion depends on E and the gas number density (N), and we can expand K(EIN) in a series [7,30,32,33]: …”

Section: -43]mentioning

confidence: 99%

“…In DMS, a(EIN) is elicited directly using a periodic time-dependent electric field E(t) that comprises short segments E+(t) with high E and longer segments L(t) with lower E of opposite polarity such that mean E over the period t c is null (the zero-offset condition) [33,[39][40][41][42][43]:…”

mentioning

confidence: 99%

“…The mobility of any ion depends on E and the gas number density (N), and we can expand K(EIN) in a series [7,30,32,33]: [1 +~a,lE/Nt] (1) 1 I, E = -f E(t)dt = 0 tc 0 (2) E͑t͒ ϭ E D F͑t͒ (3) where E D is the peak absolute amplitude ("dispersion field") and F(t) defines the functional form. The condition of F(t) asymmetry is:…”

mentioning

confidence: 99%

“…As with other filtering techniques, such as quadrupole MS, one can fix E C to monitor selected ions or scan E C to reveal the spectrum of species present. Numerous asymmetric F(t) comply with eq 2; one comprises two rectangles [33,39,40,45,46]:…”

mentioning

confidence: 99%

“…Previous efforts to optimize FAIMS waveforms [33,39,40,45] sought to maximize |E C | rather than R, i.e., a constant w 1/2 was implied. While the choice of F(t) affects the average E/N in FAIMS, and thus the average diffusion that determines the peak width [32,47], the effect on E C is much stronger, and fixing w 1/2 is a fair approximation that we follow in this work.…”

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confidence: 99%

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Optimum waveforms for differential ion mobility spectrometry (FAIMS)

Shvartsburg

Smith

2008

J. Am. Soc. Mass Spectrom.

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Differential mobility spectrometry or field asymmetric waveform ion mobility spectrometry (FAIMS) is a new tool for separation and identification of gas-phase ions, particularly in conjunction with mass spectrometry. In FAIMS, ions are filtered by the difference between mobilities in gases (K) at high and low electric field intensity (E) using asymmetric waveforms. An infinite number of possible waveform profiles make maximizing the performance within engineering constraints a major issue for FAIMS technology refinement. Earlier optimizations assumed the non-constant component of mobility to scale as E 2 , producing the same result for all ions. Here we show that the optimum profiles are defined bl the full series expansion of K(E) that includes terms beyond the first that is proportional to E . For many ionlgas pairs, the first two terms have different signs, and the optimum profiles at sufficiently high E in FAIMS may differ substantially from those previously reported, improving the resolving power by up to 2.2 times. This situation arises for some ions in all FAIMS systems, but becomes more common in recent miniaturized devices that employ higher E. With realistic K(E) dependences, the maximum waveform amplitude is not necessarily optimum, and reducing it by up to~20% to 30% is beneficial in some cases. In DMS, a(EIN) is elicited directly using a periodic time-dependent electric field E(t) that comprises short segments E+(t) with high E and longer segments L(t) with lower E of opposite polarity such that mean E over the period t c is null (the zero-offset condition) [33, 39-43]:D ifferential ion mobility spectrometry (DMS) is becoming a powerful method of broad utility for analysis of gas-phase ions and separation of their mixtures [1][2][3][4][5]. The introduction of commercial DMS instruments and particularly their integration with mass spectrometry (MS) andI or liquid or gas chromatography since 2003 has enabled rapid growth of the number and diversity of applications that include environmental analyses [6,7], food and water quality assurance [8][9][10], bacterial typing [11,12], forensic investigations [13], proteomics and metabolomics [14][15][16][17], pharmaceutical studies [18][19][20], and protein folding research [21][22][23][24][25]. Since its earliest days, DMS has been employed to detect explosives, drugs, and chemical warfare agents, and its role in defense, security, and law enforcement settings continues expanding [26][27][28][29][30][31].As captured by the name, DMS separates ions based on the difference between their mobilities (K) at high and relatively low electric field intensity (E) [1,5]. The mobility of any ion depends on E and the gas number density (N), and we can expand K(EIN) in a series [7,30,32,33]:

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“…The mobility of any ion depends on E and the gas number density (N), and we can expand K(EIN) in a series [7,30,32,33]: …”

Section: -43]mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Optimum waveforms for differential ion mobility spectrometry (FAIMS)

Shvartsburg

Smith

2008

J. Am. Soc. Mass Spectrom.

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Gas‐Phase Ion Mobility‐Mass Spectrometry (IM‐MS) and TandemIM‐MS/MSStrategies for Metabolism Studies and Metabolomics

May

Goodwin

McLean

2012

Encyclopedia of Drug Metabolism and Interactions

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This chapter describes the current and potential impact of ion mobility‐mass spectrometry (IM‐MS) for addressing the challenges of sample complexity, dynamic range, and throughput for metabolomics experiments. The four primary ion mobility techniques are described with regard to their defining analytical figures‐of‐merit. Tandem MS methods are reviewed, and novel tandem experiments made possible from multi stage activation in IM‐MS instrumentation are discussed in light of the additional information, such experiments provide for the analysis of metabolites.

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