ANALYSIS OF VOLATILE ORGANIC-COMPOUNDS IN ENVIRONMENTAL WATER SAMPLESAND SOIL-GAS BY SOLID-PHASE MICROEXTRACTION

The basic principle of solid-phase microextraction (SPME) is equilibra tion. Therefore, all possible interferences on the extraction process should be taken into account in order to perform a reliable calibratio n for the quantitative analysis of environmental samples. Humic acids and suspended mineral oxides showed no effect on the SPME analysis of volatile organic compounds (VOCs), whereas salt had a positive effect on the extraction efficiency. The linearity was good in all cases, the precision of repeated analysis was around 5% average standard deviati on, and detection limits were in the ng/l range. Thus, SPME can be app lied for the quantitative analysis of VOCs in various environmental wa ter samples, such as sea water, groundwater and heterogeneous samples like river and lake water containing suspended solids. SPME was establ ished also as an alternative to liquid-liquid extraction in the study of TiO2-catalysed photodegradation mechanisms. Finally, two new SPME s ampling probes were designed and tested for rapid, on-site measurement s of organic micropollutants in groundwater and soil gas. SPME is suit ed ideally to provide low-cost evaluation of groundwater properties in unconventional hydrogeologic settings, such as underground excavation s, and to provide preliminary data on which to base the selection of b oreholes for more extensive casing installation and instrumentation.