Average drift time and average mobility in ion mobility spectrometry

2017 ◽  
Vol 412 ◽  
pp. 20-25 ◽  
Author(s):  
Zahra Izadi ◽  
Mahmoud Tabrizchi ◽  
Hossein Farrokhpour
Keyword(s):  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Drift Time

scholarly journals On the Separation of Enantiomers by Drift Tube Ion Mobility Spectrometry

2021 ◽  
Author(s):  
Roberto Fernandez-Maestre ◽  
Markus Doerr
Keyword(s):  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Gas Flow ◽  
Drift Time ◽  
Chiral Selector ◽  
Buffer Gas ◽  
Chiral Drugs ◽  
Experimental Conditions ◽  
Chiral Selectors ◽  
Racemic Mixtures

<p><a>Racemic mixtures of twelve common </a>a-amino acids and three chiral drugs were tested for the separation of their enantiomers by ion mobility spectrometry (IMS)-quadrupole mass spectrometry (MS). Separations were tested by introducing chiral selectors in the mobility spectrometer buffer gas. (R)-α-(trifluoromethyl) benzyl alcohol, (R)-tetrahydrofuran-2-carbonitrile, (L)-ethyl lactate, methyl (S)-2-chloropropionate, and the R and S enantiomers of 2-butanol and 1-phenyl ethanol were evaluated as chiral selectors. Experimental conditions were varied during the tests including buffer gas temperature, concentration, and type of chiral selectors, analyte concentration, electrospray voltage, electrospray (ESI) solvent pH, and buffer gas flow. The individual enantiomers yielded different drift times for periods of up to 8 hours in a few experiments; such drift times were sufficiently different (~ 0.3 ms) to partially resolve the enantiomers in racemic mixtures, but these mixtures always yielded a single mobility peak at the experimental conditions tested with a drift time similar to that of one of the enantiomers. Energy calculations of the chiral selector –ion interactions showed that these separations are unlikely using 2-butanol as chiral selector but they might be feasible depending on the nature of chiral selectors and the type of enantiomers.</p>

scholarly journals A Novel Method Based on Headspace-Ion Mobility Spectrometry for the Detection and Discrimination of Different Petroleum Derived Products in Seawater

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2151
Author(s):  
Lucas Jaén-González ◽  
Ma José Aliaño-González ◽  
Marta Ferreiro-González ◽  
Gerardo F. Barbero ◽  
Miguel Palma
Keyword(s):  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Incubation Temperature ◽  
Drift Time ◽  
Sample Volume ◽  
Intermediate Precision ◽  
Injection Volume ◽  
Relative Standard ◽  
Multiple Sensor ◽  
Seawater Samples

The objective of the present study is to develop an optimized method where headspace-ion mobility spectrometry is applied for the detection and discrimination between four petroleum-derived products (PDPs) in water. A Box–Behnken design with a response surface methodology was used, and five variables (incubation temperature, incubation time, agitation, sample volume, and injection volume) with influences on the ion mobility spectrometry (IMS) response were optimized. An IMS detector was used as a multiple sensor device, in which, each drift time acts as a specific sensor. In this way, the total intensity at each drift time is equivalent to multiple sensor signals. According to our results, 2.5 mL of sample incubated for 5 min at 31 °C, agitated at 750 rpm, and with an injection volume of 0.91 mL were the optimal conditions for successful detection and discrimination of the PDPs. The developed method has exhibited good intermediate precision and repeatability with a coefficient of variation lower than 5%, (RSD (Relative Standard Deviation): 2.35% and 3.09%, respectively). Subsequently, the method was applied in the context of the detection and discrimination of petroleum-derived products added to water samples at low concentration levels (2 µL·L−1). Finally, the new method was applied to determine the presence of petroleum-derived products in seawater samples.

scholarly journals Ion Mobility Spectrometry as a Potential Tool for Flavor Control in Chocolate Manufacture

Foods ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 460
Author(s):  
Carolin Schmidt ◽  
Doris Jaros ◽  
Harald Rohm
Keyword(s):  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Mechanical Treatment ◽  
Drift Time ◽  
Principal Component ◽  
Respective Treatment ◽  
Thermo Mechanical Treatment ◽  
Processing Steps ◽  
Flavor Profile ◽  
Potential Tool

Chocolate has a complex flavor profile composed of more than 600 volatile compounds that mainly arise from the thermo-mechanical treatment during roasting and conching. The aim of this study was to evaluate the applicability of ion mobility spectrometry (IMS), as a real-time method for process monitoring in chocolate manufacture. It is evident from the ion mobility (IM) fingerprint spectra that individual processing steps affect the signal intensities at particular drift time regions. The analysis of individual IM spectra by principal component analysis (PCA) revealed that it is possible to distinguish with respect to conching temperature and time. PCA also allowed identifying those parts of the IM spectra that were predominantly affected by the respective treatment. It was, on the basis of the IM flavor fingerprints and subsequent PCA, possible to distinguish between the different states of processing of bulk cocoa. The results of the study imply that, using appropriate post-data treatment, IMS could be used for process control in cocoa processing.

scholarly journals On the Separation of Enantiomers by Drift Tube Ion Mobility Spectrometry

2021 ◽  
Author(s):  
Roberto Fernandez-Maestre ◽  
Markus Doerr
Keyword(s):  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Gas Flow ◽  
Drift Time ◽  
Chiral Selector ◽  
Buffer Gas ◽  
Chiral Drugs ◽  
Experimental Conditions ◽  
Chiral Selectors ◽  
Racemic Mixtures

<p><a>Racemic mixtures of twelve common </a>a-amino acids and three chiral drugs were tested for the separation of their enantiomers by ion mobility spectrometry (IMS)-quadrupole mass spectrometry (MS). Separations were tested by introducing chiral selectors in the mobility spectrometer buffer gas. (R)-α-(trifluoromethyl) benzyl alcohol, (R)-tetrahydrofuran-2-carbonitrile, (L)-ethyl lactate, methyl (S)-2-chloropropionate, and the R and S enantiomers of 2-butanol and 1-phenyl ethanol were evaluated as chiral selectors. Experimental conditions were varied during the tests including buffer gas temperature, concentration, and type of chiral selectors, analyte concentration, electrospray voltage, electrospray (ESI) solvent pH, and buffer gas flow. The individual enantiomers yielded different drift times for periods of up to 8 hours in a few experiments; such drift times were sufficiently different (~ 0.3 ms) to partially resolve the enantiomers in racemic mixtures, but these mixtures always yielded a single mobility peak at the experimental conditions tested with a drift time similar to that of one of the enantiomers. Energy calculations of the chiral selector –ion interactions showed that these separations are unlikely using 2-butanol as chiral selector but they might be feasible depending on the nature of chiral selectors and the type of enantiomers.</p>

scholarly journals Ion-shift reagent binding energy and the shift-mass correlation in ion mobility spectrometry

2022 ◽  
Author(s):  
Roberto Fernandez-Maestre ◽  
Mahmoud Tabrizchi ◽  
Dairo Meza-Morelos
Keyword(s):  
Molecular Weight ◽  
Binding Energy ◽  
Interaction Energy ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Drift Time ◽  
Shift Reagent ◽  
False Positives ◽  
Time Shift ◽  
Buffer Gas

Ion mobility spectrometry is widely used for the detection of illegal substances and explosives in airports, ports, custom, some stations and many other important places. This task is usually complicated by false positives caused by overlapping the target peaks with that of interferents, commonly associated with samples of interest. Shift reagents (SR) are species that selectively change ion mobilities through adduction with analyte ions when they are introduced in IMS instruments. This characteristic can be used to discriminate false positives because the interferents and illegal substances respond differently to SR depending on the structure and size of analytes and their interaction energy with SR. This study demonstrates that ion mobility shifts upon introduction of SR depend, not only on the ion masses, but on the interaction energies of the ion:SR adducts. In this study, we introduced five different SRs using ESI-IMS-MS to study the effect of the interaction energy and size on mobility shifts. The mobility shifts showed a decreasing trend as the molecular weight increased for the series of compounds ethanolamine, valinol, serine, threonine, phenylalanine, tyrosine, tributylamine, tryptophan, desipramine, and tribenzylamine. It was proved that the decreasing trend was partially due to the inverse relation between the mobility and drift time and hence, the shift in drift time better reflects the pure effect of SR on the mobility of analytes. Yet the drift time shift exhibited a mild decrease with the mass of ions. Valinol pulled out from this trend because it had a low binding energy interaction with all the SR and, consequently, its clusters were short-lived. This short lifetime produced fewer collisions against the buffer gas and a drift time shorter compared to those of ions of similar molecular weight. Analyte ion:SR interactions were calculated using Gaussian. IMS with the introduction of SR could be the choice for the free-interferents detection of illegal drugs, explosives, and biological and warfare agents. The suppression of false positives could facilitate the transit of passengers and cargos, rise the confiscation of illicit substances, and save money and distresses due to needless delays. Keywords: Adduction, ion mobility spectrometry, mass spectrometry, shift reagent, valinol, buffer gas modifier

scholarly journals Deciphering Drift Time Measurements from Travelling Wave Ion Mobility Spectrometry-Mass Spectrometry Studies

2009 ◽  
Vol 15 (2) ◽  
pp. 113-130 ◽  
Author(s):  
David P. Smith ◽  
Tom W. Knapman ◽  
Iain Campuzano ◽  
Richard W. Malham ◽  
Joshua T. Berryman ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Drift Time ◽  
Travelling Wave ◽  
Cross Sectional Area ◽  
Detailed Knowledge ◽  
Sectional Area ◽  
Cross Sectional ◽  
Biophysical Techniques

Detailed knowledge of the tertiary and quaternary structure of proteins and protein complexes is of immense importance in understanding their functionality. Similarly, variations in the conformational states of proteins form the underlying mechanisms behind many biomolecular processes, numerous of which are disease-related. Thus, the availability of reliable and accurate biophysical techniques that can provide detailed information concerning these issues is of paramount importance. Ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) offers a unique opportunity to separate multi-component biomolecular entities and to measure the molecular mass and collision cross-section of individual components in a single, rapid (≤ 2 min) experiment, providing 3D-architectural information directly. Here we report a method of calibrating a commercially available electrospray ionisation (ESI)-travelling wave ion mobility spectrometry (TWIMS)–mass spectrometer using known cross-sectional areas determined for a range of biomolecules by conventional IMS-MS. Using this method of calibration, we have analysed a range of proteins of differing mass and 3D architecture in their native conformations by ESI-TWIMS-MS and found that the cross-sectional areas measured in this way compare extremely favourably with cross-sectional areas calculated using an in-house computing method based on Protein Data Bank NMR-derived co-ordinates. This not only provides a high degree of confidence in the calibration method, but also suggests that the gas phase ESI-TWIMS-MS measurements relate well to solution-based measurements derived from other biophysical techniques. In order to determine which instrumental parameters affect the ESI-TWIMS-MS cross-sectional area calibration, a systematic study of the parameters used to optimise TWIMS drift time separations has been carried out, observing the effect each parameter has on drift times and IMS resolution. Finally, the ESI-TWIMS-MS cross-sectional area calibration has been applied to the analysis of the amyloidogenic protein β2-microglobulin and measurements for three co-populated conformational families, present under denaturing conditions, have been made: the folded, partially unfolded and unfolded states.

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