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Two methods of isolation and pre-concentration of volatile organohalogen compounds from liquid samples prior to their gas chromatographic analysis — thin layer headspace analysis with autogenous generation of the liquid sorbent and liquid-liquid extraction — were compared using model solutions of four such compounds. Statistical analysis of the results obtained was performed using (i) Dixon's Q test for the detection of outliers; (ii) Snedecor's F-test for the comparison of the precision of the determinations; (iii) Aspin-Welch's test for the comparison of the accuracies of the two methods; (iv) Student's t-test for the comparison of the mean values with the true value. It was found that the precisions and accuracies of the results obtained by the two methods did not differ significantly, while liquid-liquid extraction was much more labour- and time-consuming.

A procedure for simultaneous determination of volatile and semivolatile chloroorganic compounds (from trichloromethane to di- and trichlorobenzenes to hexachlorobutadiene) in aqueous samples was developed. The procedure is based on a DAI-GC-ECD technique widely used for trihalomethanes determination in drinking water. The DAI technique application could have been extended to semivolatile chloroorganic compounds by using a Rtx-624 (60 m x 0.32 mm I.D., df 1.8 microns (6% cyanopropyl, 94% dimethyl polysiloxane). Precision (R.S.D.) and detection limits of the DAI-GC-ECD procedure with respect to 12 volatile and semivolatile chloroorganics were determined. Relative standard deviations (R.S.D.) were lower than 22% and the detection limits (concentration equivalent to a peak height three times the baseline noise) range from 0.02 microgram L-1 for trichloroethene and tetrachloroethene to 0.25 microgram L-1 for hexachlorobutadiene to 1.6 micrograms L-1 for 1,2-dichlorobenzene. The method was successfully used to determine chloroorganic pollutants in river water.