GC Determination of 15 Organchlorine Pesticides and Polychlorobiphenyls in Soil

GC was applied to the determination of 15 organochlorine pesticides (OCP′s) and polychlorobiphenyls (PCB′s) in soil. The soil sample (10 g) was extracted with 160 mL of a mixture of n-hexane and acetone (1+1) in a water bath at 65 ℃ by soxhlet extraction for 4 h. The extract was then purified by sulfonation through shaking with portions of H2SO4. The solution was concentrated to ca. 0.5 mL by N2-blowing and made up to 1 mL with n-hexane. An aliquot of 1 μL was introduced into the HP-1 column for GC separation. ECD was used in detection. Linear relationships between values of peak area and mass concentration of the 15 compounds were kept in the same range of 1.0-100 μg·L-1, with their detection limits (3S/N) in the range of 0.080-0.16 ng·g-1. Recovery was tested by adding 20 ng of mixed standard solution of the 15 compounds to a blank sample as matrix, giving values of recovery in the range from 86.4% to 108%, with RSD′s (n=7) ranged from 2.4% to 5.2%.