Application of solid-phase microextraction to the headspace gas chromatographic analysis of semi-volatile organochlorine contaminants in aqueous matrices

Solid-phase microextraction (SPME) has been applied to the headspace gas chromatographic (HS-GC) analysis of 14 selected halogenated pesticides and contaminants ranging in volatility from hexachlorobenzene (HCB) to decachlorobiphenyl (DCBP). Elevated temperatures were employed to obtain time-efficient HS-SPME of the later-eluting analytes. A larger sample size provided improved method detection limits (MDLs, S/N=5, electrolytic conductivity detection) despite slightly reduced extraction efficiencies. With a small 15-ml sample, the HS-SPME efficiencies ranged from ca. 3 to 68%, the repeatabilities (R.S.D.) at 67-670 ng/l ranged from 5.9 to 21.7%, and the MDLs ranged from 3 to ca. 60 ng/l. With a larger 110-ml sample, repeatabilities ranged from 5.6 to 14.6%. MDLs for 10 of 14 analytes ranged from 0.3 to 0.8 ng/l and from 1.5 to 10 ng/l for the others.