共查询到20条相似文献,搜索用时 15 毫秒
1.
C. Oberhüttinger A. Langmeier H. Oberpriller M. Kessler J. Goebel G. Müller 《International Journal for Ion Mobility Spectrometry》2009,12(1):23-32
A Laser Ion Mobility Spectrometer has been set up and trace detection experiments have been performed. We find that laser
ionization almost selectively ionizes aromatic hydrocarbons. Aliphatic hydrocarbons are only laser-ionized in case these contain
conjugated double bonds. As, in contrast to radioactive ion mobility spectrometry, background air constituents and air contaminants
cannot be ionized, drift spectra are inherently simple and easily interpretable. We show that a laser ion mobility spectrometer
can be operated in two basically different modes, either using tunable or fixed-frequency laser sources. In the tunable laser
mode, aromatic hydrocarbons can be detected in the positive mode and distinguished from each other on account of their different
excitation wavelengths and ion drift times. In the fixed-frequency mode, specially chosen and intentionally admitted aromatic
hydrocarbons are laser ionized and the primary ionization is transferred to non-aromatic species by means of atmospheric pressure
chemical ionization. In this latter mode of operation nitroglycerin and triacetone triperoxide, two non-aromatic high explosives,
could be detected. 相似文献
2.
Direct detection of trimethylamine in meat food products using ion mobility spectrometry 总被引:1,自引:0,他引:1
Biogenic amines are degradation products generated by bacteria in meat products. These amines can indicate bacterial contamination or have a carcinogenic effect to humans consuming spoiled meats; therefore, their rapid detection is essential. Trimethylamine (TMA) is a good target for the detection of biogenic amines because its volatility. TMA was directly detected in meat food products using ion mobility spectrometry (IMS). TMA concentrations were measured in chicken meat juice for a quantitative evaluation of the meat decaying process. The lowest detected TMA concentration in chicken juice was 0.6 ± 0.2 ng and the lowest detected signal for TMA in a standard aqueous solution was 0.6 ng. IMS data were processed using partial least squares (PLS) and Fuzzy rule-building expert system (FuRES). Using these two chemometric methods, trimethylamine concentrations of different days of meat spoilage can be separated, indicating the decaying of meat products. Comparing the two methods, FuRES provided a better classification of different days of meat spoilage. 相似文献
3.
Process analysis using ion mobility spectrometry 总被引:7,自引:0,他引:7
Baumbach JI 《Analytical and bioanalytical chemistry》2006,384(5):1059-1070
Ion mobility spectrometry, originally used to detect chemical warfare agents, explosives and illegal drugs, is now frequently
applied in the field of process analytics. The method combines both high sensitivity (detection limits down to the ng to pg
per liter and ppbv/pptv ranges) and relatively low technical expenditure with a high-speed data acquisition. In this paper, the working principles
of IMS are summarized with respect to the advantages and disadvantages of the technique. Different ionization techniques,
sample introduction methods and preseparation methods are considered. Proven applications of different types of ion mobility
spectrometer (IMS) used at ISAS will be discussed in detail: monitoring of gas insulated substations, contamination in water,
odoration of natural gas, human breath composition and metabolites of bacteria. The example applications discussed relate
to purity (gas insulated substations), ecology (contamination of water resources), plants and person safety (odoration of
natural gas), food quality control (molds and bacteria) and human health (breath analysis). 相似文献
4.
Detection of perfluorocarbons using ion mobility spectrometry 总被引:1,自引:0,他引:1
An ISAS custom-designed ion mobility spectrometer equipped with a ionization source is used for the sensitive detection of traces of perfluorocarbons (PFCs, C5F12 to C9F20) in air, a class of substances for which a growing interest for industrial and environmental applications arose within the last years. Mobility spectra of the PFCs are presented, compared and discussed with regard to the possibility of identifying these analytes; detection limits are determined to be in the upper ng l−1 range. Using a specific PFC as an example, a way to prevent unwanted contributions of non-product ions, the difference mobility spectrum, is introduced and described. Advantages and possibilities of this technique are briefly discussed. 相似文献
5.
R.T. Vinopal J.R. JadamecP. deFur A.L. DemarsS. Jakubielski C. GreenC.P. Anderson J.E. DugasR.F. DeBono 《Analytica chimica acta》2002,457(1):83-95
Ion mobility spectrometry (IMS) is currently in widespread use for the detection and identification of narcotic and explosive compounds without prior sample clean-up or concentration steps. IMS analysis is rapid, less than a minute, and sensitive, with detection limits in the nanogram to picogram range, depending on the target analyte. Our studies indicate that this technique has potential for detection of specific components of bacterial cells and for identification and differentiation of bacterial strains and species within a minute, and with no specialized test kits or reagents required. When microgram quantities of whole bacterial cells are thermally desorbed, complex positive or negative ion patterns (plasmagrams) are obtained. These plasmagrams differ reproducibly for different strains and species and for different conditions of growth, and can be used for the classification and differentiation of specific strains and species of bacteria, including pathogens. Methods for improved ion peak detection, most notably sequential sample desorption at stepped increases in temperature (programmed temperature ramping), are described. 相似文献
6.
Vaporized water molecules are unavoidably present in every ion mobility spectrometry (IMS) measurement. In general, this humidity is seen in positive mode IMS-spectra as protonated water clusters producing reactant ions. Clusters containing water molecules are also abundant among ions generated by an analyte. In this paper the influence of humidity on IMS-spectra was systematically investigated and determined by measuring different concentrations of a selected amine at various levels of humidity. The selected amine, trimethylamine (TMA), was chosen as the model analyte due to its atmospheric importance. During the measurements, surplus water vapor was introduced into the drift section inside the IMS instrument; the concentrations of both amine and water were adjusted by controlling the gas flows. The simultaneous presence of water vapor and analyte at various predefined concentrations revealed the sensitivity of the IMS-technique to water and the effect of moisture on the ion mobility distribution. The results indicated that the existence, positions and shapes of the peaks are strongly dependent on the amount of moisture. However, the sensitivity of detection is weakly dependent on humidity if this detection is based on monomer ion peak or the sum of peaks generated by the analyte, In addition, the main principles of the adjustment of sample and water concentrations are presented here. 相似文献
7.
Bagag A Giuliani A Canon F Réfrégiers M Le Naour F 《Rapid communications in mass spectrometry : RCM》2011,25(22):3436-3440
Mass spectrometry (MS) has dramatically evolved in the last two decades and has been the driving force of the spectacular expansion of proteomics during this period. However, the very poor compatibility of MS with detergents is still a technical obstacle in some studies, in particular on membrane proteins. Indeed, the high hydrophobicity of membrane proteins necessitates the use of detergents for their extraction and solubilization. Here, we address the analytical potential of high-field asymmetric waveform ion mobility spectrometry (FAIMS) for separating peptides from detergents. The study was focused on peptides from the human integral membrane protein CD9. A tryptic peptide was mixed with the non-ionic detergents Triton X-100 or beta-D-dodecyl maltoside (DDM) as well as with the ionic detergents sodium dodecyl sulfate (SDS) or sodium deoxycholate (SDC). Although electrospray ionization (ESI) alone led to a total suppression of the peptide ion signal on mass spectra with only detection of the detergents, use of FAIMS allowed separation and clear identification of the peptide with any of the detergents studied. The detection and identification of the target compound in the presence of an excess of detergents are then feasible. FAIMS should prove especially useful in the structural and proteomic analysis of membrane proteins. 相似文献
8.
A simple procedure to analyze ammonia in ethylene by ion mobility spectrometry is described. The spectrometer is operated with a silane polymer membrane., 63Ni ion source, H+ (H2O)n reactant ion, and nitrogen drift and source gas. Ethylene containing parts per billion (ppb) (v/v) concentrations of ammonia is pulled across the membrane and diffuses into the spectrometer. Preconcentration or preseparation is unnecessary, because the ethylene in the spectrometer has no noticeable effect on the analytical results. Ethylene does not polymerize in the radioactive source. Ethylene's flammability is negated by the nitrogen inside the spectrometer. Response to ammonia concentrations between 200 ppb and 1.5 ppm is near linear, and a detection limit of 25 ppb is calculated. 相似文献
9.
Emissions from surfaces (from furniture, wall paintings or floor coverings for instance) significantly influence indoor air
quality and therefore the wellbeing or even the health of the occupants. Together with metabolites from mold they are responsible
for the well-known “sick building syndrome”. Therefore, it is in the interest of the manufacturer as well as of the occupants
to have a fast and accurate method for the detection of substances relevant to this syndrome in order to be able to monitor
and control product quality and indoor air quality. The use of small and easy-to-transport ion mobility spectrometers that
use UV light as the ionization source enables rapid in situ detection of such substances with high selectivity and sensitivity
(detection limits in the lower ppb range). If a multicapillary column is used for preseparation as well, the selectivity is
increased and the unwanted influence of humidity on the spectra can be eliminated, thus enabling the use of the instruments
under normal ambient conditions. Furthermore, the use of air as carrier gas avoids the need for other sources of high-purity
gas. An emission cell with a homogeneous and constant air flow over the surface to be investigated was developed in order
to ensure reproducible results. Investigations of emissions from wooden surfaces with and without additional contamination
as well as from complex mixtures are presented. The results demonstrate that relevant emissions can be identified and quantified
with high sensitivity and selectivity in under five minutes. Therefore, the method is useful for indoor air quality monitoring,
especially when miniaturized instruments are applied.
Figure 相似文献
10.
11.
Due to the proteomics revolution, multi-dimensional separation and detection instruments are required to evaluate many peptides and proteins in single samples. In this study, electrospray ionization (ESI) ion mobility spectrometry (IMS) was evaluated as an additional separation after HPLC separations. Common HPLC mobile phase compositions (solvents, acid modifiers, and buffers) were assessed for the effect on ESI-IMS response. Up to 5 mM sodium phosphate, a non-volatile buffer, was able to be electrosprayed into the IMS without degradation of the instrumental performance. Due to the rapid separation times of IMS, multiple IMS spectra were obtained within a single HPLC peak. A five-peptide mixture was separated in a capillary HPLC column under isocratic conditions within 3 min. Coelution of two peaks due to non-optimal HPLC conditions occurred and these two peaks could not be distinguished by HPLC with UV detection. In contrast, the single ion mobility chromatograms provided separation of each peptide as well as providing a second degree of analyte identification (HPLC retention time and IMS mobility). Furthermore, IMS-MS analysis of the five peptides and comparison with HPLC retention times showed that each peptide had a unique retention time-ion mobility-mass to charge value. This work showed that IMS could be employed for direct separation and detection of HPLC eluents and also could be combined with HPLC-MS for three unique dimensions of separation. 相似文献
12.
Characterizing ion mobility and collision cross section of fatty acids using electrospray ion mobility mass spectrometry 下载免费PDF全文
Fang Zhang Su Guo Manyu Zhang Zhixu Zhang Yinlong Guo 《Journal of mass spectrometry : JMS》2015,50(7):906-913
This study investigated the ion mobility (IM) and the collision cross section (CCS) of fatty acids (FAs) using electrospray IM MS. The IM analysis of 18 FA ions showed intriguing differences among the saturated FAs, monounsaturated FAs, multi‐unsaturated FAs, and cis‐isomer/trans‐isomer with respect to the aliphatic tail chains. The length of aliphatic tail chain present in the ion structures had a strong influence on the differentiation of drift, while the number of double bond showed a weaker influence. The tiny drift differences between cis‐isomer and trans‐isomer were also observed. In the CCS measurements, two internal standards were involved in the mobility calibration and accuracy estimation. It insured our empirical CCS values were of high experimental precision (±0.35% or better) and accuracy (±0.25% or better). Moreover, the mass‐to‐charge ratio (m/z) – mobility plots obtained by ion mobility spectrometry with mass spectrometry analysis of FAs – was used to investigate the structural relationship between the molecules. Each series of FAs sharing a similar structure was aligned in the linear plot. Finally, the developed procedure was applied to the determination of FAs in rat adipose tissues, and it allowed the presence of 13 FAs to be confirmed with their exact masses and CCS values. These studies reveal the direct relationship between the behaviors in IM and the molecular structures and thus may provide further validations to the FA identification process. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
13.
Joanna Rudnicka Paweł Mochalski Agapios Agapiou Milt Statheropoulos Anton Amann Bogusław Buszewski 《Analytical and bioanalytical chemistry》2010,398(5):2031-2038
The aim of the present study was to evaluate the suitability of ion mobility spectrometry (IMS) for the detection of human
urine as an indication of human presence during urban search and rescue operations in collapsed buildings. To this end, IMS
with a radioactive ionization source and a multicapillary column was used to detect volatile organic compounds (VOCs) emitted
from human urine. A study involving a group of 30 healthy volunteers resulted in the selection of seven volatile species,
namely acetone, propanal, 3-methyl-2-butanone, 2-methylpropanal, 4-heptanone, 2-heptanone and octanal, which were detected
in all samples. Additionally, a preliminary study on the permeation of urine volatiles through the materials surrounding the
voids of collapsed buildings was performed. In this study, quartz sand was used as a representative imitating material. Four
compounds, namely 3-methyl-2-butanone, octanal, acetone and 2-heptanone, were found to permeate through the sand layers during
all experiments. Moreover, their permeation times were the shortest. Although IMS can be considered as a potential technique
suitable for the detection, localization and monitoring of VOCs evolved from human urine, further investigation is necessary
prior to selecting field chemical methods for the early location of trapped victims. 相似文献
14.
During the investigation of the degradation products of 2,4,6-trinitrotoluene (TNT) using ion mobility spectrometry (IMS), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (DCP) were found to have IMS responses which overlapped those of the TNT degradation products. It was observed that the Cl(-) reactant ion chemistry, often used for explosives analysis, was not always successful in resolving peak overlap of analytes and interferents. It is shown here that resolution of the analytes and interferences can sometimes be achieved using only air for the formation of reactant ions, at other times through the use of Br(-) as an alternative to Cl(-) for producing reactant ions, and also through the promotion of adduct stability by lowering the IMS temperature. 相似文献
15.
The use of ion mobility spectrometry systems to detect explosives in high security situations creates a need to determine compounds that interfere and may compromise accurate detection. This is the first study to identify possible interfering air contaminants common in airport settings by IMS. Seventeen suspected contaminants from four major sources were investigated. Due to the ionization selectivity gained by employing chloride reactant ion chemistry, only 7 of the 17 compounds showed an IMS response. Of those seven compounds, only 4,6-dinitro-o-cresol (4,6DNOC) was found to have a similar mobility to 2,4,6-trinitrotoluene (TNT) with K(o) values of 1.55 and 1.50 cm(2) V(-1) s(-1), respectively. Although baseline resolution between TNT and 4,6DNOC was not achieved, the drift time for TNT was still easily identified. Alkyl-nitrated phenols, due to acidic fog, responded the strongest in the IMS. The effect of contamination on TNT sensitivity was investigated. Charge competition between TNT and 2,4-dinitrophenol (2,4DNP) was found to occur and to effect TNT sensitivity. 相似文献
16.
Investigation of drift gas selectivity in high resolution ion mobility spectrometry with mass spectrometry detection 总被引:3,自引:0,他引:3
Matz LM Hill HH Beegle LW Kanik I 《Journal of the American Society for Mass Spectrometry》2002,13(4):300-307
Recent studies in electrospray ionization (ESI)/ion mobility spectrometry (IMS) have focussed on employing different drift gases to alter separation efficiency for some molecules. This study investigates four structurally similar classes of molecules (cocaine and metabolites, amphetamines, benzodiazepines, and small peptides) to determine the effect of structure on relative mobility changes in four drift gases (helium, nitrogen, argon, carbon dioxide). Collision cross sections were plotted against drift gas polarizability and a linear relationship was found for the nineteen compounds evaluated in the study. Based on the reduced mobility database, all nineteen compounds could be separated in one of the four drift gases, however, the drift gas that provided optimal separation was specific for the two compounds. 相似文献
17.
A method to measure the rate constant for the formation of symmetrical proton-bound dimers at ambient pressure was proposed. The sample is continuously delivered to the drift region of an ion mobility spectrometer where it reacts with a swarm of monomer ions injected by the shutter grid. Dimer ions are formed in the drift tube and a tail appears in the ion mobility spectrum. The rate constant is derived from the mobility spectra. The proposed approach was typically examined for methyl isobutyl ketone (MIBK), 2,4-dimethyl pyridine (DMP), and dimethyl methyl phosphonate (DMMP). The rate constants measured in this study were: 0.25 × 10−9, 0.86 × 10−10, and 0.47 × 10−10 cm3 s−1 for MIBK, DMP and DMMP, respectively. The logarithm of the measured rate constants were found to be almost independent of reciprocal temperature within 303 to 343 K, indicating that no activation energy is involved in the formation of proton-bound dimers. 相似文献
18.
Mark Levin Alexey Krisilov Boris Zon Gary Eiceman 《International Journal for Ion Mobility Spectrometry》2014,17(2):73-77
We present the study of expansion of an ion cloud in the process of its drift in the ion mobility spectrometer taking into account the influence of diffusion and electric field of the space charge of the ion cloud. Nonlinear integro-differential equation describing these effects was obtained and solved numerically in the one-dimensional case. We found a threshold value of the ion density, above which the nonlinear effects associated with the space-charge field become significant, which agrees well with the experimental data and the criterion of Spangler. These nonlinear effects lead to the fact that the spatial ion distribution ceases to be Gaussian, and with good accuracy are approximated by the distribution of Kohlrausch–Williams–Watts. 相似文献
19.
Z. Hashemian 《Talanta》2010,81(3):1081-8607
A new method based on corona discharge ion mobility spectrometry (CD-IMS) was developed for the analysis of biogenic amines including spermidine, spermine, putrescine, and cadaverine. The ion mobility spectra of the compounds were obtained with and without n-Nonylamine used as the reagent gas. The high proton affinity of n-Nonylamine prevented ion formation from compounds with a proton affinity lower than that of n-Nonylamine and, therefore, enhanced its selectivity. It was also realized that the ion mobility spectrum of n-Nonylamine varied with its concentration. A sample injection port of a gas chromatograph was modified and used as the sample introduction system into the CD-IMS. The detection limits, dynamic ranges, and analytical parameters of the compounds with and without using the reagent gas were obtained. The detection limits and dynamic ranges of the compounds were about 2 ng and 2 orders of magnitude, respectively. The wide dynamic range of CD-IMS originates from the high current of the corona discharge. The results revealed the high capability of the CD-IMS for the analysis of biogenic amines. 相似文献
20.
Methyl tert-butyl ether (MTBE) is commonly used as chemical additive to increase oxygen content and octane rating of reformulated gasoline. Despite its impact on enhancing cleaner combustion of gasoline, MTBE poses a threat to surface and ground water when gasoline is released into the environment. Methods for onsite analysis of MTBE in water samples are also needed. A less common technique for MTBE detection from water is ion mobility spectrometry (IMS). We describe a method for fast sampling and screening of MTBE from water by solid phase microextraction (SPME) and IMS. MTBE is adsorbed from the head space of a sample to the coating of SPME fiber. The interface containing a heated sample chamber, which couples SPME and IMS, was constructed and the SPME fiber was introduced into the sample chamber for thermal desorption and IMS detection of MTBE vapors. The demonstrated SPME-IMS method proved to be a straightforward method for the detection of trace quantities of MTBE from waters including surface and ground water. We determined the relative standard deviation of 8.3% and detection limit of 5 mg L−1 for MTBE. Because of short sampling, desorption, and detection times, the described configuration of combined SPME and IMS is a feasible method for the detection of hazardous substances from environmental matrices. 相似文献