Fingerprint identification of volatile organic compounds in gasoline contaminated groundwater using gas chromatography differential ion mobility spectrometry

Groundwater can be contaminated when e.g. gasoline tanks leak. Due to sampling and lab analysis, groundwater monitoring is time consuming and expensive. The technologies developed for rapid on-site analysis of gasoline contaminated groundwater face the technical limitation to distinguish the gasoline from complex matrices. In the present study the fingerprint identification of volatile organic components (VOCs) in gasoline contaminated groundwater using gas chromatography (GC) differential ion mobility spectrometry (DMS) is investigated. Groundwater was spiked with five sorts of gasoline (one reformulated gasoline, gasoline without additives and three different brand gasoline collected on petrol stations) and analyzed by GC-DMS. Seven VOCs (benzene, toluene, ethyl benzene, m-xylene, p-xylene, o-xylene, 1,2,4-trimethylbenzene) were identified by GC mass spectrometry (GC-MS) as well as by GC-DMS and selected as markers. The semi-quantitative determination of the selected compounds was achieved. The limits of detection of the GC-DMS are 46.42?ng for benzene, 1.13?ng for toluene, 1.80?ng for ethylbenzene, 0.22?ng for m-xylene, 1.13?ng for p-xylene, 0.61?ng for o-xylene and 0.37?ng for 1,2,4-trimethylbenzene, respectively. These results reveal the feasibility of GC-DMS for on-site monitoring of contaminated groundwater.