APPLICATION OF SOLID-PHASE MICROEXTRACTION AND GAS-CHROMATOGRAPHY WITH ELECTRON-CAPTURE AND MASS-SPECTROMETRIC DETECTION FOR THE DETERMINATION OF HEXACHLOROCYCLOHEXANES IN SOIL SOLUTIONS

Solid-phase microextraction (SPME) is a method for the extraction of organic compounds from aqueous samples. The analytes are extracted into a stationary phase placed on a fused-silica fibre and are thermally desorbed in the injector of a gas chromatograph. The connection of GC with electron-capture (ECD) and mass spectrometric (MS) detection with the SPME method makes it possible to determine low concentrations of organochlorine compounds in aqueous solutions. With hexachlorocyclohexanes (HCHs) detection limits between 5 ng/l (for alpha- and gamma-HCH with the combination of SPME and GC-ECD) and 80 ng/l (for beta-HCH with the combination of SPME and GC-MS) were calculated. The SPME-GC method was used to investigate the mobility of HCHs in wetland soils near Bitterfeld. The results of this study show the high mobility of beta-HCH despite the low water solubility and the long persistence of beta-HCH in soils. The proportion of beta-HCH in the total HCH concentration is higher in soil solutions (80-90%) than in soils.