A CONTINUOUS LIQUID-LIQUID-EXTRACTION SYSTEM COUPLED ONLINE WITH CAPILLARY GAS-CHROMATOGRAPHY FOR ENVIRONMENTAL AND ECOTOXICOLOGICAL ANALYSIS

The applicability of a liquid-liquid extraction system which is couple d on-line with a capillary gas chromatograph was studied for environme ntal and ecotoxicological analyses. The optimized and automated system was used for the determination of apolar and rather non-volatile orga nic compounds in aqueous samples. Relevant aspects of sample introduct ion, phase separation and selection of extraction solvent are discusse d. Three routine-type applications are described, vis. an improved met hod for the determination of hexachlorocyclohexanes in ground water an d the determination of the so-called NCC-ether and ACC-ether in ecotox icological studies. Depending on the application studied, the concentr ation levels varied from 0.1 to 6000 mu g/l, using ECD and/or FID dete ction. Typical coefficients of variation obtained with the total extra ction-GC procedure were 2-25 %. The system was found to be rugged, it saves time compared with set-ups involving off-line liquid-liquid extr action and considerably reduces the manual work load.