Small polar organic pollutants have been discovered to be great threats to the groundwater' as they often are highly mobile and persistent in the environment. 1,2,4-Triazole and N,N-dimethylsulfamide, two well-known examples of small polar compounds, are frequent pollutants of upper groundwater. Both are degradation products of several fungicides commonly or previously used in agriculture' but also in wood-preserving paints. A common trait in the analysis of these small polar compounds is the lack of sufficient pre-concentration methods to lower the limit of detection and enable quantitative analysis at nano-scale concentrations. To date, they are analyzed only by direct injection in HPLC-MS/MS, with detection limits just below the European threshold value for pesticides in groundwater of 0.1 μg/L. Based on a comprehensive method development, a solid phase extraction method was developed. As known LC methods for analysis of 1,2,4-triazole are based on Thermo Fisher's Hypercarb column, emphasis was placed on testing various carbon-based materials. The final, thoroughly validated extraction protocol is based on Supelco's ENVI-Carb Plus cartridges. With extraction recoveries close to 100% for 1,2,4-triazole and N,N-dimethylsulfamide and quantification limits of around 0.003 μg/L, the method enables extraction and quantification of polar pollutants at nano-scale concentration from groundwater samples. In addition, the method is very promising to be used for other small polar pollutants. Graphical abstract.
Keywords: ENVI-Carb; Hypercarb; LC-MS/MS; PMOCs; SPE; Solid phase extraction.