Implementing of Fourier Deconvolution Multiplexing to Fast Polarity Switching Miniaturized Ion Mobility Spectrometer.

Ion mobility spectrometry (IMS) is a reliable and sensitive technique for the detection and analysis of compounds at the trace level. Depending on the chemical composition of the sample, compounds may be positively or negatively charged to form different polarity ions and detected in positive or negative polarity of the electric field. In order to detect multiple threats simultaneously with miniaturized devices, using a single detection unit to achieve high resolving power and high sensitivity is important. In this work, a miniaturized drift tube with fast polarity switching capabilities integrated with Fourier deconvolution multiplexing techniques is proposed for the first time as a means to improve the performance of ion mobility spectrometry. The sensitivity and resolving power are improved compared to traditional polarity switching signal averaging data acquisition methods. The displayed device had a high resolving power up to 52 at a drift length of 41 mm and a drift tube voltage of 2 kV. Trinitrotoluene (TNT), methamphetamine (MA), benzene, toluene, methyl tert-butyl ether (MTBE), acetic acid, and methylene chloride were evaluated using the proposed fast polarity switching multiplexing spectrometer and exhibited satisfied performance.

High-performance liquid chromatography analysis of alkaloids in various parts of lotus extracts with ion mobility spectrometry and mass spectrometry dual detection.

Using high-performance liquid chromatography coupled with electrospray ionization-ion mobility spectrometry and mass spectrometry, we proposed a dual-detection method for the identification and profiling of alkaloids in various lotus parts including leaf, plumule, stem, seed epicarp, and receptacle. The eluent from high-performance liquid chromatography was split and conducted to electrospray ionization-ion mobility spectrometry and time-of-flight mass spectrometry separately to facilitate the compound identification. In total, 23 kinds of alkaloids were identified based on m/z, drift time, and retention time, including alkaloid isomers such as lirinidine, N-nornuciferine, and O-nornuciferine with identical m/z that are difficult to differentiate using mass spectrometry alone. Using this method, we investigated the changing dynamics of alkaloid accumulation in lotus leaves and lotus stems at different harvesting periods. The total alkaloid content showed an increasing trend with the growth and development of leave and stem. Overall, the developed dual detection method has the advantages of high peak capacity and high sensitivity compared with the conventional detection method and facilitates the identification of detected compounds.

Miniaturized Photo-Ionization Fourier Deconvolution Ion Mobility Spectrometer for the Detection of Volatile Organic Compounds.

Because of its simplicity, reliability, and sensitivity, the drift tube ion mobility spectrometer (IMS) has been recognized as the equipment of choice for the on-site monitoring and identification of volatile organic compounds (VOCs). However, the performance of handheld IMS is often limited by the size, weight, and drift voltage, which heavily determine the sensitivity and resolving power that is crucial for the detection and identification of VOCs. In this work, we present a low-cost, miniaturized drift tube ion mobility spectrometer incorporated with a miniaturized UV ionization lamp and a relatively low drift voltage. The sensitivity and resolving power are boosted with the implementation of Fourier deconvolution multiplexing compared to the conventional signal averaging data acquisition method. The drift tube provides a high resolving power of up to 52 at a drift length of 41 mm, 10 mm ID dimensions, and a drift voltage of 1.57 kV. Acetone, benzene, dimethyl methyl phosphonate, methyl salicylate, and acetic acid were evaluated in the developed spectrometer and showed satisfactory performance.