Determining the water content of a drift gas using reduced ion mobility measurements

Hauck, Brian C.; Davis, Eric J.; Clark, Aurora E.; Siems, William F.; Harden, Charles S.; McHugh, Vincent M.; Hill, Herbert H.

doi:10.1016/j.ijms.2014.05.010

Cited by 16 publications

(20 citation statements)

References 29 publications

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“…The lower precision of NH 3 (NH 4 ) + supports the recommendation that the reactant ion peak not be used for calibration purposes. 22 The trends seen in Figure 2 are very similar to previous results 15 but are more accurate. Either an increase in the drift gas water content or a decrease in the drift gas temperature caused K 0 values to decrease.…”

Section: ■ Results and Discussionsupporting

confidence: 85%

“…As previously seen, the protonated monomer (DMMPH + , m/z 125) and the proton bound dimer of DMMP ((DMMP) 2 H + , m/z 249) were also present, but were only fragments of the ammoniated species in the vacuum interface and did not form freely in the drift tube. 15 Through analysis of the two-dimensional ToF-MS spectrum for fragment ions, it was found that DMMPH + fragmented primarily from DMMPNH 4…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…11 These applications rely on the knowledge of the reduced mobility (K 0 ) values of ions, which are calculated from the measured drift time (t d ) of the ion across the length (L) of the instrument under a voltage (V) gradient applied across L, and is normalized to standard temperature (T) and pressure (P), as shown in eq 1. 12 = 15 760…”

mentioning

confidence: 99%

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High Accuracy Ion Mobility Spectrometry for Instrument Calibration

et al. 2018

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Ion mobility spectrometry (IMS) is widely used to characterize compounds of interest (COIs) based on their reduced mobility ( K) values. In an attempt to increase the accuracy and agreement of studies, the most recommended method has been to use a reference compound with a known K value to calibrate the instrument and calculate COI K values from normalized spectra. Researchers are limited by the accuracy of previous K value reference measurements on which to base their calibrations. Any inaccuracy in these reference K values, typically ±2%, will propagate through to the calculated K value of the COI. For this reason, there is a need to standardize reference K values with improved accuracy. Through improvement of the accuracy of reference measurements, a lower degree of error will propagate through new K value calculations. The K values of the ammonium reactant ion, the potential reference standard dimethyl methylphosphonate (DMMP), and three explosive COIs were characterized at multiple drift gas temperatures, drift gas water contents, and electric field strengths on an accurate ion mobility spectrometry instrument. K values reported here are known to ±0.1% as a result of reducing the error of all instrumental parameters.

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Section: ■ Results and Discussionsupporting

confidence: 85%

Section: ■ Results and Discussionmentioning

confidence: 99%

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High Accuracy Ion Mobility Spectrometry for Instrument Calibration

et al. 2018

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“…In a clever application, Hauck et al turned one disadvantage of IMS into a benefit. They determined the moisture content of the buffer gas in IMS field operations using the ratio of mobilities of the protonated monomer and proton‐bound dimer ions of DMMP, sensitive and insensitive, respectively, to the formation of water cluster ions . This is an application of the 2‐chemical‐standards calibration procedure (Section 15).…”

Section: Applications Of Mobility Shifts Upon Injection Of Buffer Gasmentioning

confidence: 99%

Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications, predictions of mobility shifts, and influence of interaction energy and structure

Fernandez‐Maestre

2018

J Mass Spectrom

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Ion mobility spectrometry (IMS) is an analytical technique used for fast and sensitive detection of illegal substances in customs and airports, diagnosis of diseases through detection of metabolites in breath, fundamental studies in physics and chemistry, space exploration, and many more applications. Ion mobility spectrometry separates ions in the gas-phase drifting under an electric field according to their size to charge ratio. Ion mobility spectrometry disadvantages are false positives that delay transportation, compromise patient's health and other negative issues when IMS is used for detection. To prevent false positives, IMS measures the ion mobilities in 2 different conditions, in pure buffer gas or when shift reagents (SRs) are introduced in this gas, providing 2 different characteristic properties of the ion and increasing the chances of right identification. Mobility shifts with the introduction of SRs in the buffer gas are due to clustering of analyte ions with SRs. Effective SRs are polar volatile compounds with free electron pairs with a tendency to form clusters with the analyte ion. Formation of clusters is favored by formation of stable analyte ion-SR hydrogen bonds, high analytes' proton affinity, and low steric hindrance in the ion charge while stabilization of ion charge by resonance may disfavor it. Inductive effects and the number of adduction sites also affect cluster formation. The prediction of IMS separations of overlapping peaks is important because it simplifies a trial and error procedure. Doping experiments to simplify IMS spectra by changing the ion-analyte reactions forming the so-called alternative reactant ions are not considered in this review and techniques other than drift tube IMS are marginally covered.

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“…As the motion of ions in a neutral gas is often accompanied by complex ion molecule reactions, the effective ion temperature has a profound effect on the reduced ion mobilities observed in IMS. In particular, the formation of ion bound water clusters according to reaction (4) affects the effective ion temperature having a major influence on the reduced ion mobility 6,7 .…”

Section: Introductionmentioning

confidence: 99%

Field-Dependent Reduced Ion Mobilities of Positive and Negative Ions in Air and Nitrogen in High Kinetic Energy Ion Mobility Spectrometry (HiKE-IMS)

Allers

Kirk

Schaefer

et al. 2020

J. Am. Soc. Mass Spectrom.

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In High Kinetic Energy Ion Mobility Spectrometry (HiKE-IMS), ions are formed in a reaction region and separated in a drift region, which is similar to classical drift tube ion mobility spectrometers (IMS) operated at ambient pressure. However, in contrast to the latter, the HiKE-IMS is operated at decreased background pressure of 10 -40 mbar and achieves high reduced electric field strengths of up to 120 Td in both the reaction and the drift region. Thus, the HiKE-IMS allows insights into the chemical kinetics of ion bound water cluster systems at effective ion temperatures exceeding 1000 K, although it is operated at the low absolute temperature of 45 °C. In this work, a HiKE-IMS with high resolving power of R P = 140 is used to study the dependence of reduced ion mobilities on the drift gas humidity and the effective ion temperature for the positive reactant ions H 3 O + (H 2 O) n , O 2 + (H 2 O) n , NO + (H 2 O) n , NO 2 + (H 2 O) n , and NH 4 + (H 2 O) n , as well as the negative reactant ions O 2 -(H 2 O) n , O 3 -(H 2 O) n , CO 3 -(H 2 O) n , HCO 3 -(H 2 O) n , and NO 2 -(H 2 O) n . By varying the reduced electric field strength in the drift region, cluster transitions are observed in the ion mobility spectra. This is demonstrated for the cluster systems H 3 O + (H 2 O) n and NO + (H 2 O) n .

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Determining the water content of a drift gas using reduced ion mobility measurements

Cited by 16 publications

References 29 publications

High Accuracy Ion Mobility Spectrometry for Instrument Calibration

High Accuracy Ion Mobility Spectrometry for Instrument Calibration

Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications, predictions of mobility shifts, and influence of interaction energy and structure

Field-Dependent Reduced Ion Mobilities of Positive and Negative Ions in Air and Nitrogen in High Kinetic Energy Ion Mobility Spectrometry (HiKE-IMS)

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