Ion mobility spectrometry in carbon dioxide

Rokushika, Souji; Hatano, Hiroyuki; Hill, Herbert H.

doi:10.1021/ac00293a022

Cited by 36 publications

(26 citation statements)

References 20 publications

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“…While nitrogen is one of the most common drift gases used in IMS, the variation of drift times with polarizability of the drift gas has been reported for a number of analytes using different gases or mixtures including air, nitrogen, helium, argon, CO 2 and SF 6 [35][36][37][38]. General conclusions drawn from these reports are that the polarizability of the drift gas can dramatically affect not only overall drift times but also the order of arrival times for various molecules [35].…”

Section: Different Drift Gases Markedly Affect the Separation Of Isommentioning

confidence: 95%

Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS)

Dwivedi

Bendiak

Clowers

et al. 2007

J. Am. Soc. Mass Spectrom.

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162

167

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Carbohydrates are an extremely complex group of isomeric molecules that have been difficult to analyze in the gas phase by mass spectrometry because (1) precursor ions and product ions to successive stages of MS(n) are frequently mixtures of isomers, and (2) detailed information about the anomeric configuration and location of specific stereochemical variants of monosaccharides within larger molecules has not been possible to obtain in a general way. Herein, it is demonstrated that gas-phase analyses by direct combination of electrospray ionization, ambient pressure ion mobility spectrometry, and time-of-flight mass spectrometry (ESI-APIMS-TOFMS) provides sufficient resolution to separate different anomeric methyl glycosides and to separate different stereoisomeric methyl glycosides having the same anomeric configuration. Reducing sugars were typically resolved into more than one peak, which might represent separation of cyclic species having different anomeric configurations and/or ring forms. The extent of separation, both with methyl glycosides and reducing sugars, was significantly affected by the nature of the drift gas and by the nature of an adducting metal ion or ion complex. The study demonstrated that ESI-APIMS-TOFMS is a rapid and effective analytical technique for the separation of isomeric methyl glycosides and simple sugars, and can be used to differentiate glycosides having different anomeric configurations.

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Section: Different Drift Gases Markedly Affect the Separation Of Isommentioning

confidence: 95%

Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS)

Dwivedi

Bendiak

Clowers

et al. 2007

J. Am. Soc. Mass Spectrom.

Self Cite

162

167

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“…e K 0 (0) is from references [50]; a, b were derived from measured CVs [7]. f K 0 (0) is from reference [51] (measurements at ambient conditions); a, b were derived from measured CVs [7]. g K 0 (0) is extrapolated from the measurements for Cl Ϫ (ϳ 2.9) [52] and Br Ϫ (ϳ 2.5) [53]; a, b are from reference [39].…”

Section: Analytical Gap Width and Waveform Frequencymentioning

confidence: 99%

Optimization of the design and operation of FAIMS analyzers

Shvartsburg

Tang

Smith

2005

J. Am. Soc. Mass Spectrom.

141

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Field asymmetric waveform ion mobility spectrometry (FAIMS) holds significant promise for post-ionization separations in conjunction with mass-spectrometric analyses. However, a limited understanding of fundamentals of FAIMS analyzers has made their design and operation largely an empirical exercise. Recently, we developed an a priori simulation of FAIMS that accounts for both ion diffusion (including anisotropic components) and Coulomb repulsion, and validated it by extensive comparisons with FAIMS/MS data. Here it is corroborated further by FAIMS-only measurements, and applied to explore how key instrumental parameters (analytical gap width and length, waveform frequency and profile, the identity and flow speed of buffer gas) affect FAIMS response. We find that the trade-off between resolution and sensitivity can be managed by varying gap width, RF frequency, and (in certain cases) buffer gas, with equivalent outcome. In particular, the resolving power can be approximately doubled compared to "typical" conditions. Throughput may be increased by either accelerating the gas flow (preferable) or shortening the device, but below certain minimum residence times performance deteriorates. Bisinusoidal and clipped-sinusoidal waveforms have comparable merit, but switching to rectangular waveforms would improve resolution and/or sensitivity. For any waveform profile, the ratio of two between voltages in high and low portions of the cycle produces the best performance. (J Am Soc Mass Spectrom 2005, 16, 2-12) © 2004 American Society for Mass Spectrometry S eparation of gas-phase ionic mixtures by field asymmetric waveform ion mobility spectrometry (FAIMS) extends back over a decade in the technical literature [1][2][3], but has attracted a broad interest in the analytical and mass-spectrometry communities only recently [4 -29]. FAIMS separates ions by the difference between mobilities at high (K H ) and low (K L ) electric fields, in other words the average slope of mobility as a function of field, K(E). The form of K(E) may be complex: with increasing E, mobilities (of both cations and anions) may increase (termed species of Type A), decrease (Type C), or initially increase, but decrease at yet higher E (Type B) [4,5]. Usually, small and structurally rigid species belong to Type A and large flexible ones (e.g., proteins) belong to Type C. K(E) can be represented by a polynomial of even powers of E/N:At moderately high E/N relevant to FAIMS (up to ϳ60 -80 Td), eq 1 can usually be truncated after theExperimentally, a gas stream entraining ions passes between two electrodes that carry a time-dependent potential V D (t) that alternates between "high" and "low" voltages, such that the integral value over the cycle is null but time-averaged positive and negative voltages differ [4,5]. Then only a hypothetical ion with constant K(E) would be transmitted, while species exhibiting variable K(E) drift towards one of the electrodes and eventually neutralize upon impact [4,5]. For a particular ion, this may be prevented by applying ...

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“…Each term of eq (3) is a functional of ion-molecule collision integrals that depend on the gas temperature 29 Therefore, as well-known in IMS, 38,74,75 the separation parameters in ion mobility methods of any order are temperature-dependent. The effect generally increases for higher n, where small changes of mobility as a function of temperature are magnified by differential measurement.…”

Section: The Effect Of Temperaturementioning

confidence: 99%

Feasibility of Higher-Order Differential Ion Mobility Separations Using New Asymmetric Waveforms

2006

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Technologies for separating and characterizing ions based on their transport properties in gases have been around for three decades. The early method of ion mobility spectrometry (IMS) distinguished ions by absolute mobility that depends on the collision cross section with buffer gas atoms. The more recent technique of field asymmetric waveform IMS (FAIMS) measures the difference between mobilities at high and low electric fields. Coupling IMS and FAIMS to soft ionization sources and mass spectrometry (MS) has greatly expanded their utility, enabling new applications in biomedical and nanomaterials research. Here, we show that time-dependent electric fields comprising more than two intensity levels could, in principle, effect an infinite number of distinct differential separations based on the higher-order terms of expression for ion mobility. These analyses could employ the hardware and operational procedures similar to those utilized in FAIMS. Methods up to the 4 th or 5 th order (where conventional IMS is 1 st order and FAIMS is 2 nd order) should be practical at field intensities accessible in ambient air, with still higher orders potentially achievable in insulating gases. Available experimental data suggest that higher-order separations should be largely orthogonal to each other and to FAIMS, IMS, and MS.Approaches to separation of ion mixtures and characterization of ions in the gas phase based on ion mobility are becoming commonplace in analytical chemistry. The key advantage of gas-phase separations over condensed phase methods is the exceptional speed enabled by rapid molecular motion in gases. This inherent benefit is made increasingly topical by the growing focus of analytical technology on higher throughput. Since their first demonstration a decade ago, 1-3 instrumental platforms combining electrospray ionization (ESI) or matrixassisted laser desorption ionization (MALDI) sources with ion mobility separations and mass-spectrometry (MS) have undergone a sustained development that has improved their resolution and sensitivity to the levels demanded by practical applications. 4-10 Recent commercial introduction of such systems 11-14 is expanding interest in ion mobility/MS, particularly for analyses of complex biological samples such as proteolytic digests and lipids, nucleotides, and metabolites. [15][16][17][18][19][20][21][22][23][24] Single-stage ion mobility spectrometry (IMS) was investigated since the 1970s, 25-27 with a noteworthy development of ESI/IMS in 1980s. 28 In IMS, ions drift through a non-reactive buffer gas under the influence of a modest electric field. The drift velocity (v) in the field of intensity E is determined by ion mobility (K):(1)For consistency, measured mobilities are normally converted to reduced values K 0 by adjusting the buffer gas temperature (T, Kelvin) and pressure (P, Torr) to standard (STP) conditions:NIH Public Access

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Ion mobility spectrometry in carbon dioxide

Cited by 36 publications

References 20 publications

Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS)

Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS)

Optimization of the design and operation of FAIMS analyzers

Feasibility of Higher-Order Differential Ion Mobility Separations Using New Asymmetric Waveforms

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