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1.
一种微型FAIMS传感器芯片的研制 总被引:1,自引:0,他引:1
基于微机电系统(MEMS)技术,研制了一种微型高场非对称波形离子迁移谱(FAIMS)传感器芯片.芯片尺寸为18.8mm×12.4mm×1.2mm,由离子化区、迁移区、离子检测区组成.采用真空紫外灯离子源在大气压环境下对样品进行离子化,经过离子化区中聚焦电极的电场作用,实现离子在进入迁移区之前的聚焦,提高离子信号的强度.通过在上下玻璃上溅射Au/Cr(300nm/30nm)金属,并与厚度为200μm、采用感应耦合等离子体(ICP)工艺刻蚀的硅片键合,形成迁移区的矩形通道,尺寸为10mm×5mm×0.2mm.离子检测区为三排直径200μm、间距100μm交错排列的圆柱阵列式微法拉第筒,能同时检测正负离子.采用频率为2MHz,最大电压为364V,占空比为30%的高场非对称方波电压进行FAIMS芯片实验.以丙酮和甲苯为实验样品,载气流速80L·h-1,补偿电压从-10V到3V以0.1V的步长进行扫描,得到了丙酮和甲苯的FAIMS谱图,验证了FAIMS芯片的性能.丙酮和甲苯的FAIMS-MS实验进一步表明FAIMS系统实现了离子分离和过滤功能. 相似文献
2.
Ridha Mabrouki Ryan T. Kelly David C. Prior Alexandre A. Shvartsburg Keqi Tang Richard D. Smith 《Journal of the American Society for Mass Spectrometry》2009,20(9):1768-1774
Differential mobility spectrometry or field asymmetric waveform ion mobility spectrometry (FAIMS) is gaining broad acceptance
for analyses of gas-phase ions, especially in conjunction with largely orthogonal separation methods such as mass spectrometry
(MS) and/or conventional (drift tube) ion mobility spectrometry. In FAIMS, ions are filtered while passing through a gap between
two electrodes that may have planar or curved (in particular, cylindrical) geometry. Despite substantial inherent advantages
of the planar configuration and its near-universal adoption in current stand-alone FAIMS devices, commercial FAIMS/MS systems
have employed curved FAIMS geometries that can be more effectively interfaced to MS. Here we report a new planar (p-) FAIMS
design with slit-shaped entrance and exit apertures that substantially increase ion transmission in and out of the analyzer.
The entrance slit interface effectively couples p-FAIMS to multi-emitter electrospray ionization (ESI) sources, improving
greatly the ion current introduced to the device and allowing liquid flow rates up to ∼50 μL/min. The exit slit interface
increases the transmission of ribbon-shaped ion beams output by the p-FAIMS to downstream stages such as a MS. Overall, the
ion signal in ESI/FAIMS/MS analyses increases by over an order of magnitude without affecting FAIMS resolution. 相似文献
3.
Matthew J. Pollard Christopher K. Hilton Hongli Li Kimberly Kaplan Richard A. Yost Herbert H. HillJr. 《International Journal for Ion Mobility Spectrometry》2011,14(1):15-22
Since the development of electrospray ionization (ESI) for ion mobility spectrometry mass spectrometry (IMMS), IMMS have been
extensively applied for characterization of gas-phase bio-molecules. Conventional ion mobility spectrometry (IMS), defined
as drift tube IMS (DT-IMS), is typically a stacked ring design that utilizes a low electric field gradient. Field asymmetric
ion mobility spectrometry (FAIMS) is a newer version of IMS, however, the geometry of the system is significantly different
than DT-IMS and data are collected using a much higher electric field. Here we report construction of a novel ambient pressure
dual gate DT-IMS coupled with a FAIMS system and then coupled to a quadrupole ion trap mass spectrometer (QITMS) to form a
hybrid three-dimensional separation instrument, DT-IMS-FAIMS-QITMS. The DT-IMS was operated at ~3 Townsend (electric field/number
density (E/N) or (Td)) and was coupled in series with a FAIMS, operated at ~80 Td. Ions were mobility-selected by the dual
gate DT-IMS into the FAIMS and from the FAIMS the ions were detected by the QITMS for as either MS or MSn. The system was evaluated using cocaine as an analytical standard and tested for the application of separating three isomeric
tri-peptides: tyrosine-glycine-tryptophan (YGW), tryptophan-glycine-tyrosine (WGY) and tyrosine-tryptophan-glycine (YWG).
All three tri-peptides were separated in the DT-IMS dimension and each had one mobility peak. The samples were partially separated
in the FAIMS dimension but two conformation peaks were detected for the YWG sample while YGW and WGY produced only one peak.
Ion validation was achieved for all three samples using QITMS. 相似文献
4.
Separation of Ions from Volatile Organic Compounds Using High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometer 下载免费PDF全文
A combination of high-field asymmetric waveform ion mobility spectrometry (FAIMS) with mass spectrometer (MS) was analyzed. FAIMS separates ions from the volatile organic compounds in the gas-phase as an ion-filter for MS. The sample ions were created at ambient pressure by ion source, which was equipped with a 10.6 eV UV discharge lamp (λ=116.5 nm).The drift tube of FAIMS is composed of two parallel planar electrodes and the dimension is 10 mm×8 mm×0.5 mm. FAIMS was investigated when driven by the high-filed rectangular asymmetric waveform with the peak-to-peak voltage of 1.36 kV at the frequency of 1 MHz and the duty cycle of 30%. The acetone, the butanone, and their mixture were adopted to characterize the FAIMS-MS. The mass spectra obtained from MS illustrate that there are ion-molecular reactions between the ions and the sample neutral molecular. And the proton transfer behavior in the mixture of the acetone and the butanone is also observed.With the compensation voltage tuned from -30 V to 10 V with a step size of 0.1 V, the ion pre-separation before MS is realized. 相似文献
5.
Purves RW Barnett DA Ells B Guevremont R 《Journal of the American Society for Mass Spectrometry》2000,11(8):738-745
High-field asymmetric waveform ion mobility spectrometry (FAIMS) was used to separate gas-phase conformers of bovine ubiquitin produced by electrospray ionization. These conformers were sampled by a triple quadrupole mass spectrometer where energy-loss experiments, following the work of Douglas and co-workers, were used to determine their cross sections. The measured cross sections for some conformers were readily altered by the voltages applied to the interface ion optics, therefore very gentle mass spectrometer interface conditions were required to preserve gas-phase conformers separated by FAIMS. Cross sections for 19 conformers (charge states +5 through +13) were measured. Two conformers for the +12 charge state, which were readily separated in FAIMS, were found to have similar cross sections. Based on a method to calibrate the collision gas thickness, the cross sections measured using the FAIMS/energy-loss method were compared with literature values determined using drift tube ion mobility spectrometry. The comparison illustrated that the conformers of bovine ubiquitin that were identified using drift tube ion mobility spectrometry were also observed using the FAIMS device. 相似文献
6.
High-field asymmetric waveform ion mobility spectrometry (FAIMS) separates ions at atmospheric pressure and room temperature based on the difference of the mobility of ions in strong electric fields and weak electric fields. This field-dependent mobility of an ion is reflected in the compensation voltage (CV) at which the ion is transmitted through FAIMS, at a given asymmetric waveform dispersion voltage (DV). Experimental CV, relative peak ion intensity, and peak width data were compared for three FAIMS prototypes with concentric cylindrical electrodes having inner/outer electrode radii of: (1) 0.4/0.6 cm, (2) 0.8/1.0 cm, and (3) 1.2/1.4 cm. The annular analyzer space was 0.2 cm wide in each case. A finite-difference numerical computation method is described for evaluation of peak shapes and widths in a CV spectrum collected using cylindrical geometry FAIMS devices. Simulation of the radial distribution of the ion density in the FAIMS analyzer is based upon calculation of diffusion, electric fields, and the electric fields introduced by coulombic ion-ion repulsion. Excellent agreement between experimental and calculated peak shapes were obtained for electrodes of wide diameter and for ions transmitted at low CV. 相似文献
7.
Ruotolo BT McLean JA Gillig KJ Russell DH 《Journal of the American Society for Mass Spectrometry》2005,16(2):158-165
The influence of field strength on the separation of tryptic peptides by drift tube-based ion mobility-mass spectrometry is reported. Operating the ion mobility drift tube at elevated field strengths (expressed in V cm(-1) torr(-1)) reduces separation times and increases ion transmission efficiencies. Several accounts in the literature suggest that performing ion mobility separation at elevated field strength can change the selectivity of ion separation. To evaluate the field strength dependant selectivity of ion mobility separation, we examined a data set of 65 singly charged tryptic peptide ion signals (mass range 500-2500 m/z) at six different field strengths and four different drift gas compositions (He, N2, Ar, and CH4). Our results clearly illustrate that changing the field strength from low field (15 V cm(-1) torr(-1)) to high field (66 V cm(-1) torr(-1)) does not significantly alter the selectivity or peak capacity of IM-MS. The implications of these results are discussed in the context of separation methodologies that rely on the field strength dependence of ion mobility for separation selectivity, e.g., high-field asymmetric ion mobility spectrometry (FAIMS). 相似文献
8.
Mahmoud Tabrizchi Elham Khezri 《International Journal for Ion Mobility Spectrometry》2008,11(1-4):19-25
The peak width, shape and position are heavily affected by ion–molecule reactions which are inevitable in the drift region of an ion mobility spectrometer. This paper discusses three major types of reactions occurring in drift tube and their effects on the shape and displacement of the peaks. The first reaction is the dissociation of dimer ions during their flight time creating a tail for the monomer peak. The second one is the reaction between the monomer ions with molecules of the same kind in the drift region. Such a process shifts the peak to longer drift times and causes a tail for the peak as well as its broadening. The last one is the reaction of ions with molecules of different types such as dopant which may exist in the drift region. Depending on the reactivity of the ions, this kind of reaction displaces the peaks differently so that peak-to-peak resolution is lost or, in some cases, gained. 相似文献
9.
10.
Guevremont R Thekkadath G Hilton CK 《Journal of the American Society for Mass Spectrometry》2005,16(6):948-956
High-field asymmetric waveform ion mobility spectrometry (FAIMS) separates ions at atmospheric pressure based on the difference in the mobility of an ion in a strong electric field and in a weak electric field. This field-dependent mobility of an ion is reflected in the compensation voltage (CV) at which the ion is transmitted through FAIMS at an applied asymmetric waveform dispersion voltage (DV). In this report, we show that experimental CV peak shapes using dome tipped inner electrode FAIMS prototypes with inner/outer electrode radii of: (1) 0.2/0.4 cm and (2) 0.4/0.6 cm are a function of the longitudinal position of the inner electrode. Varying the longitudinal position of the inner electrode modifies the electric fields between the surfaces of the hemispherical shaped inner electrode and the outer electrode in the vicinity of the ion outlet. In this region the position-dependent electric field strength (E/N) effectively forms a second tandem FAIMS analyzer region having differing ion separation properties. The final tandem FAIMS separation is the intersection of the CV windows of these two differing FAIMS separations and, therefore, the peak width in the CV scan is dependent on the longitudinal tip displacement (LTD) of the inner electrode. CV scans are shown for a LTD range of 0.14 to 0.4 cm. These scans illustrate that it is possible to control the FAIMS resolution (CV/peak width) from about 1 for the 0.2/0.4 cm electrode set at intermediate longitudinal position to over 10 at the narrowest distance between the inner electrode and the ion outlet. 相似文献
11.
Mark Kwasnik Facundo M. Fernández 《Rapid communications in mass spectrometry : RCM》2010,24(13):1911-1918
We present a detailed investigation of the performance of our previously reported nanoelectrospray high‐resolution resistive‐glass atmospheric pressure drift tube ion mobility spectrometer constructed with monolithic resistive‐glass desolvation and drift regions. Using experimental spectral data and theoretical pulse width and diffusion variables, we compare theoretical and experimental resolving powers achievable under a variety of field strengths and ion gate pulse widths. The effects of instrumental and operational parameters on the resolution achievable in chromatographic terms are also discussed. Following characterization of the separation power of the instrument, experimental spectral peak width data is fitted by a least‐squares procedure to a pre‐existing semi‐empirical model developed to study contributions to peak width other than initial pulse width and diffusional broadening. The model suggests possible contributions to the final measured peak width from electric field inhomogeneity and minor contributions from instrumental parameters such as anode size, anode‐to‐anode grid distance and drift gas flow rate. The model also reveals an unexpected ion gate width dependence on the final measured peak width that we attribute to non‐ideal performance of the Bradbury‐Nielsen ion gate and limitations in the design of our pulsing‐electronics. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
12.
Shvartsburg AA Tang K Smith RD 《Journal of the American Society for Mass Spectrometry》2004,15(10):1487-1498
Field asymmetric waveform ion mobility spectrometry (FAIMS) is rapidly gaining acceptance as a robust, versatile tool for post-ionization separations prior to mass-spectrometric analyses. The separation is based on differences between ion mobilities at high and low electric fields, and proceeds at atmospheric pressure. Two major advantages of FAIMS over condensed-phase separations are its high speed and an ion focusing effect that often improves sensitivity. While selected aspects of FAIMS performance are understood empirically, no physical model rationalizing the resolving power and sensitivity of the method and revealing their dependence on instrumental variables has existed. Here we present a first-principles computational treatment capable of simulating the FAIMS analyzer for virtually any geometry (including the known cylindrical and planar designs) and arbitrary operational parameters. The approach involves propagating an ensemble of ion trajectories through the device in real time under the influence of applied asymmetric potential, diffusional motion incorporating the high-field and anisotropic phenomena, and mutual Coulomb repulsion of ionic charges. Calculations for both resolution and sensitivity are validated by excellent agreement with measurements in different FAIMS modes for ions representing diverse types and analyte classes. 相似文献
13.
《International journal of mass spectrometry》2007,259(1-3):87-95
Protonated poly(ethylene glycol), produced by electrospray ionization (ESI), with molecular weights ranging from 0.3 to 5 kDa and charge states from 1+ to 7+ were characterized using high-field asymmetric waveform ion mobility spectrometry (FAIMS). Results for all but some of the 3+ and 4+ charge states are consistent with a single gas-phase conformer or family of unresolved conformers for each of these charge states. The FAIMS compensation voltage scans resulted in peaks that could be accurately fit with a single Gaussian for each peak. The peak widths increase linearly with compensation voltage for maximum ion transmission but do not depend on m/z or molecular weight. Fitting parameters obtained from the poly(ethylene glycol) data were used to analyze conformations of oxidized and reduced lysozyme formed from different solutions. For oxidized lysozyme formed from a buffered aqueous solution, a single conformer (or group of unresolved conformers) was observed for the 7+ and 8+ charge states. Two conformers were observed for the 9+ and 10+ charge states formed from more denaturing solutions. Data for the fully reduced form indicate the existence of up to three different conformers for each charge state produced directly by ESI and a general progression from a more extended to a more folded structure with decreasing charge state. These results are consistent with those obtained previously by proton-transfer reactivity and drift tube ion mobility experiments, although more conformers were identified for the fully reduced form of lysozyme using FAIMS. 相似文献
14.
15.
Elistratov AA Sherbakov LA 《European journal of mass spectrometry (Chichester, England)》2007,13(2):115-123
The effect of space charge on the ion beam in a spectrometer of ion mobility increment with the planar drift chamber has been investigated. A model for the drift of ions under a non-uniform high-frequency electric field(1-3) has been developed recently. We have amplified this model by taking space charge effect into account. The ion peak shape taking into consideration the space charge effect is obtained. The output current saturation effect limiting the rise of the ion peak with increasing ion density at the input of the drift chamber of a spectrometer is observed. We show that the saturation effect is caused by the following phenomenon. The maximum possible output ion density exists, depending on the ion type (constant ion mobility, k(0)) and the time of the motion of ions through the drift chamber. At the same time, the ion density does not depend on the parameters of the drift chamber. 相似文献
16.
A new two-dimensional ion mobility spectrometry approach combined with mass spectrometry has been used to examine ubiquitin ions in the gas phase. In this approach ions are separated in an initial drift tube into conformation types (defined by their collision cross sections) and then a gate is used to introduce a narrow distribution of mobility-separated ions into a second drift tube for subsequent separation. The results show that upon selection a narrow peak shape is retained through the second drift tube. This requires that at 300 K the selected distribution does not interconvert substantially within the broader range of structures associated with the conformation type within the approximately 10-20 ms time scale of these experiments. For the [M + 7H]7+ ion, it appears that many ( approximately 5-10) narrow selections can be made across each of the compact, partially-folded, and elongated conformer types, defined previously (Int. J. Mass Spectrom. 1999, 187, 37-47). 相似文献
17.
Ruwan T. Kurulugama Fabiane M. Nachtigall Sunyoung Lee Stephen J. Valentine David E. Clemmer 《Journal of the American Society for Mass Spectrometry》2009,20(5):729-737
A new method that allows a linear drift tube to be operated as a continuous ion mobility filter is described. Unlike conventional
ion mobility instruments that use an electrostatic gate to introduce a packet of ions into a drift region, the present approach
uses multiple segmented drift regions with modulated drift fields to produce conditions that allow only ions with appropriate
mobilities to pass through the instrument. In this way, the instrument acts as a mobility filter for continuous ion sources.
By changing the frequency of the applied drift fields it is possible to tune this instrument to transmit ions having different
mobilities. A scan over a wide range of drift field frequencies for a single ion species shows a peak corresponding to the
expected resonance time of the ions in one drift region segment and a series of peaks at higher frequencies that are overtones
of the resonant frequency. The measured resolving power increases for higher overtones, making it possible to resolve structures
that were unresolved in the region of the fundamental frequency. We demonstrate the approach by examining oligosaccharide
isomers, raffinose and melezitose as well as a mixture of peptides obtained from enzymatic digestion of myoglobin. 相似文献
18.
Marilyn Prieto Richard A. Yost 《International Journal for Ion Mobility Spectrometry》2011,14(2-3):61-69
High-field asymmetric waveform ion mobility spectrometry (FAIMS) can operate at atmospheric pressure to separate gas-phase ions on the basis of a difference in the mobility of an ion at high fields relative to its mobility at low field strengths. Several novel cell geometries have been proposed in addition to the commercially available planar and cylindrical designs. Nevertheless, there is still much to explore about three-dimensional (3-D) curved cell geometries (spherical and hemispherical) and comparison to two-dimensional (2-D) curved geometries (cylindrical). The geometry of a FAIMS cell is one of the essential features affecting the transmission, resolution, and resolving power of FAIMS. Electric fields in a spherical design allow advantages such as virtual potential wells that can induce atmospheric-pressure near-trapping conditions and help reduce ion losses. Curvature of electrodes enables the ions to remain focused near the gap median, which help to improve sensitivity and ion trapping at higher pressures. Here we detail the design and characterization of a novel FAIMS cell having spherical electrode geometry and compare it to hemispherical and cylindrical cells. These FAIMS cells were interfaced with a quadrupole ion trap mass spectrometer in this study. Several structural classes of common explosives were employed to evaluate the separation power of these geometries. FAIMS spectra were generated by scanning the compensation voltage (CV) while operating the mass spectrometer in total ion mode. The identification of ions was accomplished through mass spectra acquired at fixed values of CVs. The performance of FAIMS using cylindrical, hemispherical, and spherical cells was compared and trends identified. For all trials, the best transmission was obtained by the spherical FAIMS cell while hemispherical FAIMS provided the best resolution and resolving power. 相似文献
19.
High-field asymmetric waveform ion mobility spectrometry: a new tool for mass spectrometry 总被引:1,自引:0,他引:1
Guevremont R 《Journal of chromatography. A》2004,1058(1-2):3-19
High-field asymmetric waveform ion mobility spectrometry (FAIMS) is a new technology for ion separation at atmospheric pressure. This review introduces the reader to FAIMS, covering topics ranging from the fundamentals and extraction of physical parameters from the raw data, to applications of FAIMS extending from homeland security to environmental analysis to proteomics. The investigation of FAIMS as an ion pre-processing tool for mass spectrometry is in its infancy, but reports in the literature illustrate that FAIMS separates isobaric ions including diastereoisomers, separates isotopes, reduces background ions by isolating ions of interest, and simplifies spectra of complex mixtures by dividing the mixture into a series of simpler subsets of ions. Applications ranging from quantitative analysis of inorganic and organometallic compounds, to studies of the conformers of intact proteins, have been reported. This review is a launching point for further exploration of FAIMS. 相似文献
20.
Shvartsburg AA Bryskiewicz T Purves RW Tang K Guevremont R Smith RD 《The journal of physical chemistry. B》2006,110(43):21966-21980
Approaches to separation and characterization of ions based on their mobilities in gases date back to the 1960s. Conventional ion mobility spectrometry (IMS) measures the absolute mobility, and field asymmetric waveform IMS (FAIMS) exploits the difference between mobilities at high and low electric fields. However, in all previous IMS and FAIMS experiments ions experienced an essentially free rotation; thus the separation was based on the orientationally averaged cross-sections Omega(avg) between ions and buffer gas molecules. Virtually all large ions are permanent electric dipoles that will be oriented by a sufficiently strong electric field. Under typical FAIMS conditions this will occur for dipole moments >400 D, found for many macroions including most proteins above approximately 30 kDa. Mobilities of aligned dipoles depend on directional cross-sections Omega(dir) (rather than Omega(avg)), which should have a major effect on FAIMS separation parameters. Here we report the FAIMS behavior of electrospray-ionization-generated ions for 10 proteins up to approximately 70 kDa. Those above 29 kDa exhibit a strong increase of mobility at high field, which is consistent with predicted ion dipole alignment. This effect expands the useful FAIMS separation power by an order of magnitude, allowing separation of up to approximately 10(2) distinct protein conformers and potentially revealing information about Omega(dir) and ion dipole moment that is of utility for structural characterization. Possible approaches to extending dipole alignment to smaller ions are discussed. 相似文献