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This study presents an efficient approach for the precise detection of chlorine gas (Cl2) and hydrogen chloride (HCl), harmful pollutants frequently emitted from chlor-alkali and various industrial processes. These substances, even in trace amounts, pose significant health risks. Ion mobility spectrometry (IMS), known for its sensitivity in pollutant detection, traditionally struggles to differentiate between Cl2and HCl due to the similarity of their product ions, Cl−. To overcome this limitation, we introduce a novel technique combining dopant-assisted negative photoionization ion mobility spectrometry (DANP-IMS) with an automatic semiconductor cooling system. This unique combination utilizes the differential cryogenic removal efficiencies of Cl2and HCl to segregate these gases before analysis. By applying DANP-IMS, we achieved selective measurement of Cl−ion signal intensities under both standard and cryogenic conditions, facilitating the accurate quantification of total chlorine and Cl2levels. We then determined HCl concentrations by deducting the Cl2signal from the total chlorine readings. Our approach demonstrated detection limits of 2.0 parts per billion (ppb) for Cl2and 0.8 ppb for HCl, across a linear detection range of 0–200 ppb. Moreover, our method's capability for real-time atmospheric monitoring of Cl2and HCl near industrial sites underscores its utility for environmental monitoring, offering a robust solution for the separate and precise measurement of these pollutants.

Ammonia (NH3) plays an important role in the atmospheric environment such as the formation of PM2.5, the concentration monitoring of which could hence help in the air quality assessment. In this study, a method for quantitative monitoring of atmospheric NH3was developed based on modifier-enhanced selectivity detection using a homemade vacuum ultraviolet photoionization ion mobility spectrometry (VUV-PI-IMS). To enhance the resolution and sensitivity of measuring NH3, 2-butanone as the gas modifier was introduced into the drift tube with the drift gas. Atmospheric NH3can be selectively detected, where the peak-to-peak resolution (RP-P) of 7.69 was obtained. The product ions were identified to be [C4H8O]2NH4+by using a homemade time-of-flight mass spectrometer. The calculated limit of detection (LOD) was 0.39 ppbv improving about 10 times. For the most common concentration variation of atmospheric NH3in the range of 10–100 ppbv, the linear curve was obtained with R2of 0.997. Lastly, the VUV-PI-IMS was used to monitor the evolution of atmospheric NH3near our laboratory and mounted on a car for monitoring the regional distribution of atmospheric NH3in Dalian, China. The results also showed that VUV-PI-IMS has a promising application prospect in monitoring the concentration of atmospheric NH3and supporting the air quality assessment.

Anticoagulant rodenticide diphacinone (DPN) with the common form of sodium diphacinone (SDPN), playing an important role in controlling field rodents and mice in homes, is harmful to both human beings and domestic animals while taken mistakenly or poisoned intentionally. In this work, we propose a simple and rapid method based on thermal desorption ion mobility spectrometry (TD-IMS) for detecting DPN and SDPN. SDPN, with ultra-low vapour pressure, was essentially measured in the form of DPN after its in situconversion with the assistance of an acid. Under the optimal conditions, the limits of detection (S/N= 3) for SDPN and DPN were less than 0.15 ng μL−1while their recoveries were 96% and 97%, respectively, and the relative standard deviation for five measurements was less than 6.15%. Finally, the current method was used to detect DPN and SDPN in beverages including green tea, cola, and coffee, demonstrating its capacity in the application for actual samples.