Determination of Organochlorine Pesticides and Chlorobenzene Compounds in Water by Headspace Solid-Phase Microextraction Combined with Gas Chromatography

Objective To establish a method for determination of organochlorine pesticides and chlorobenzene compounds in water by using headspace solid-phase microextraction(HS-SPME)coupled with GC. Methods 100 μm PDMS was used as SPME fiber. At 1 150 r/min with magnetic stiring,extraction time was 30 min,temperature was 80 ℃. The injector temperature was held at 270 ℃ and desorption time was 5 min. The column pressure was set at 80 kPa. Make-up flow rate was at a constant of 20 ml/min. The septum purge was set at 5 ml/min. The injector was used in splitless mode for 3 min and then in split mode at the rate of 24∶1. The ECD system was maintained at 300 ℃. Results The limit of detection (LOD) of 1,4-dichlorobenzene was 8.633 ng/L in the range of 0.39 to 19.56 μg/L. The LOD of 1,2-dichlorobenzene was 4.023 ng/L in 0.35 to 17.68 μg/L. The LOD of 1,3,5- trichlorobenzene was 0.148 ng/L in 0.007 7 to 0.38 μg/L. The LOD of 1,2,4-trichlorobenzene was 0.124 ng/L in 0.009 to 0.48 μg/L. The LOD of 1,2,3-trichlorobenzene was 0.099 ng/L in 0.007 9 to 0.39 μg/L. The LOD of hexachlorobenzene was 0.005 ng/L in 0.000 4 to 0.02 μg/L. The LOD of heptachlor was 0.073 ng/L in 0.001 to 0.05 μg/L. The LOD of chlorothalonil was 0.277 ng/L in 0.096 to 4.83 μg/L. The LOD of α-HCH was 0.013 ng/L in 0.008 to 0.40 μg/L. The LOD of β-HCH was 0.353 ng/L in 0.04 to 2.00 μg/L. The LOD of γ-HCH was 0.06 ng/L in 0.008 to 0.40 μg/L. The LOD of δ-HCH was 1.25 ng/L in 0.04 to 2.00 μg/L. The LOD of p,p’-DDE was 0.03 ng/L in 0.030 to 0.10 μg/L. The LOD of o,p’-DDT was 0.122 ng/L in 0.008 to 0.40 μg/L. The LOD of p,p’- DDD was 0.066 ng/L in 0.004 to 0.20 μg/L. The LOD of p,p’-DDT was 0.464 ng/L in 0.02 to 1.00 μg/L. A good linearity was obtained,r 0.99. The recovery rates were 72.25% -109.0% with the relative standard deviation (RSD) of 1.82% -11.61% . Conclusion The method is fast,simple,sensitive and needs no organic solvent and it is applicable to the determination of organochlorine pesticides and chlorobenzene compounds in water.