Application of portable gas chromatography–mass spectrometer for rapid field based determination of TCE in soil vapour and groundwater

• Published in: Environmental technology & innovation Vol. 21; p. 101274
• Main Authors: Wang, Liang, Cheng, Ying, Naidu, Ravi, Chadalavada, Sreenivasulu, Bekele, Dawit, Gell, Peter, Donaghey, Mark, Bowman, Mark
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2021
• Subjects: case studies; environmental technology; groundwater; Portable gas chromatography–mass spectrometer (GC–MS); quantitative analysis; Retractable soil vapour sampling probe; soil air; Solid-phase micro-extraction (SPME); spectrometers; subsurface soil layers; Three-dimensional (3D) mapping; trichloroethylene; Trichloroethylene (TCE); United States Environmental Protection Agency; vapors; Vapour intrusion; volatile organic compounds; Trichloroethylene (TCE); Three-dimensional (3D) mapping; Vapour intrusion; Portable gas chromatography–mass spectrometer (GC–MS); Retractable soil vapour sampling probe; Solid-phase micro-extraction (SPME)
• ISSN: 2352-1864; 2352-1864
• DOI: 10.1016/j.eti.2020.101274

The application of portable chromatography–mass spectrometer (GC–MS) is restrained by its detection limits without the development of proper sample pre-concentration methods. The primary focus of this paper is to introduce a practical field measurement methodology for the analysis of volatile organic compounds (VOCs) in soil vapour and groundwater using a portable gas (GC–MS)system for application to in situ assessment of vapour intrusion from VOC contamination. A solid-phase micro-extraction (SPME) technique was applied for sample pre-concentration before the GC–MS​ measurement. Practical in-field soil gas SPME sampling methods have been developed to optimise the SPME extraction efficiency to then ultimately improve the detection limits of portable GC–MS. An Australian site impacted by a chlorinated VOC, trichloroethylene (TCE), was the subject of the case study. To rapidly assess soil vapour samples in subsurface soil, in-house-developed retractable soil vapour sampling probes (SVSPs) were installed at the site in clusters at depths of 1 m, 2 m and 3 m below ground level at each sampling location. Use of the SVSPs for sampling enabled the generation of a three-dimensional map and distribution contours for TCE concentrations using the in situ measurement results of a portable GC–MS analysis for vapour intrusion investigation. The results of the portable GC–MS​ analysis were compared with the results from conventional USEPA methods, such as TO-15 and Method 8265 for soil vapour and groundwater samples, respectively. This work demonstrates that the developed methodology of using a portable GC–MS system has the capability for in-field quantitative analysis of VOCs for rapid contaminated site vapour intrusion assessment. [Display omitted] •A novel field-based soil vapour VOC detection method using a portable GC–MS​ system.•In-house-developed retractable soil vapour probes were installed for sampling.•3D distribution contour map for TCE concentrations in soil vapour was generated.