Evaluation of GC-ICP-MS method for the determination of volatile metal(loid) compounds in environmental gas samples
The aim of this study is to perform multielemental determinations of volatile organometal(loid) compounds (VOMs) in environmental gases such as landfill gas and sewage sludge fermentation gases. The analytical method focuses on the on-line coupling of capillary GC with ICP-TOF-MS and provide excellent separation as well as sensitive element selective detection. It involves a cryotrapping step for these (VOMs) such as hydrides, methylated and permethylated species of e.g. As, Sb, Sn, Bi, Hg, Pb etc. In-house standards were generated in Tedlar® bags and a classical external calibration (R2 >0.99) was applied. The precision of injections was good (RSD = 3-11%, N=10) and the standards were reproducibly generated (RSD = 3.20%, N=3). A total number of 4 landfill sites and 5 sewage sludge treatment sites were sampled. One landfill site contained 15 different Sn-compounds, 5 species of which had a concentration of more than 13 ng/l, with a maximum concentration of 1050 ng/l for Me4Sn. Overall, the concentration range of most of the Sn-compounds was 0,01-0,5 ng/l and some unknown species could also be identified. In addition, the permethylated species of As, Se, Sb and Bi could be detected in the range of 0,01 – 117 ng/l. Although their concentration was usually relatively low (at 0,01 – 0,09 ng/l), the variety of volatile Sn-compounds in the sludge fermentation gas samples was quite astonishing. Me3Bi and Me3Sb were the dominant species in the sludge fermentation gases at concentrations of up to 42 ng/l.