Low-Temperature Plasma Ionization Ion Mobility Spectrometry

Abstract

In this research work, the capability of low-temperature plasma (LTP) as an ionization source for ion mobility spectrometry (IMS) has been investigated for the first time. This new ionization source enhances the potential of IMS as a portable analytical tool and allows direct analysis of various chemical compounds without having to evaporate the analyte or seek a solvent or reagent whatsoever. The effects of parameters such as the flow rate of the discharge gas, plasma voltage, and positioning of the LTP on the IMS signal were investigated. The positive reactant ions generated by the LTP ionization source were similar to those created in a corona discharge ionization source, where the proton clusters ((H(2)O)(n)H(+)) are the most abundant reactant ion, and in the negative mode, in addition to a saturated electron peak, several negative reactant ions (e.g., NO(x)(-)) were observed too. These reactant ions subsequently ionized the gaseous samples directly and liquids or solids after evaporation by plasma desorption. The ion mobility spectra of a few selected compounds, including explosives, drugs, and amines, were obtained to evaluate the new ionization source in positive and negative modes, and the reduced mobility values (K(0)) of the originated ions were calculated. Furthermore, the method has also been applied to obtain the figures of merit for acetaminophen as a test compound. The results obtained are promising enough to ensure the use of LTP as a desorption/ionization source in IMS for analytical applications.

Simultaneous Determination of Nitrite and Nitrate in Potato and Water Samples Using Negative Electrospray Ionization Ion Mobility Spectrometry

“…18 A variety of ionization sources, including radioactive sources (e.g. 63 Ni), corona discharge, photoionization, electrospray ionization (ESI), and very recently low-temperature plasma 19 have been used for IMS. However, most of these ionization sources are used for the analysis of volatile and semi-volatile organic compounds.…”

Evaluation of Non-Contact Sampling and Detection of Explosives using Receiver Operating Characteristic Curves

“…The reduced mobility of explosives and illicit drugs from the LTP source were similar to the previously reported values, forming similar cluster ions as from traditional IMS ionization sources with figures of merit similar to that of LTP-MS instruments [166].…”

“…The interface of the LTP source with an IMS system was performed by Jafari [165] in which a conical ring was used in the reaction region so that the drift gas was allowed to be exhausted prior to entering the reaction region, thus resulting in minimal disruption of the LTP plasma plume. The IMS design…”

Time-resolved spectroscopy of a homogeneous dielectric barrier discharge for soft ionization driven by square wave high voltage

“…They are easy to set up in simple and compact way, have low power consumption, and can operate over a wide pressure range with different discharge gasses. Therefore, the DBDs have found a wide range of analytical applications, such as the DBD atomizer for analytical atomic spectrometry [2,3], DBD detector for gas chromatography [4], DBD-induced and/or assisted chemiluminescence [5,6], and as the ionization source for ion-mobility spectrometry [7]. A comprehensive presentation of the history, principles, development, applications, and future prospects of this ionization source can be found in several reviews and articles [8][9][10][11][12][13].…”