PURGE-AND-TRAP INJECTION CAPILLARY GAS-CHROMATOGRAPHIC DETERMINATION OF VOLATILE AROMATIC-HYDROCARBONS IN RIVER SEDIMENT

Dynamic headspace and purge-and-trap with methanolic extraction techni ques for the simple and rapid determination of trace amounts of volati le aromatic hydrocarbons in river sediments were compared. The purge-a nd-trap technique with metanolic extraction using an external standard method gives a better representativeness of the analysed sample, a tw ofold higher precision and twofold lower detection limits. When the in ternal standard method is applied, the precision of both methods incre ases 3-4 times and the detection limits decrease 4-5 times.