An investigation of the formation of taste and odour contaminants in surface water using the headspace SPME-GC-MS method

The aim of this study was to optimize of a method for determining of compounds which are responsible for the earthy/musty odour in surface water. Among taste and odour contaminants the following compounds are mentioned: (+/-)-geosmin, 2-methylisoborneol, 2,4,6-trichoroanisole, 2-isopropyl-3-methoxypyrazine and 2-isobutyl-3-methoxypyrazine. Some experiments were performed to examine the extraction conditions such as fiber exposure time, temperature of extraction and salt addition. Various SPME fibers such as PDMS, CAR/PDMS and PDMS/DVB coatings were used for the isolation of tested compounds from water samples. As tested, compounds 2-methylisoborneol, 2-isopropyl-3-methoxypyrazine and 2-isobutyl-3-methoxypyrazine were used. After SPME optimization, real surface water samples were examined using the SPME-GC/MS method. Based on preliminary experiments the qualitative and quantitative analyses for the determination of (+/-)-geosmin, 2-methylisoborneol and 2,4,6-trichloroanisole were performed. The regression coefficients for calibration curves for examined compounds are R²≥0.990. This shows that the used method is linear in the examined concentration range (from 20.32 to 168.00 ng/L). one of the reasons for the formation of taste and odour contaminants can be surface water pollution. The changes of water conditions such as temperature, pH and conductivity were examined. And, for the test of periodical changes of geosmin concentration in surface water samples, the experiments were performed in various seasons.