[Determination of kepone residue in seawater by gas chromatography coupled with electron capture detector].

The effects of extraction solvent, capillary column, cleanup method, co-eluted analytes and other influencing factors on the detection of kepone in seawater were investigated. The analytical method of gas chromatography (GC) coupled with electron capture detector (ECD) was established to determine kepone in seawater. In the method, liquid-liquid extraction and sulfuric acid cleanup were used in the sample pre-processing. Chromatographic analysis was performed on a DB-5 capillary column with external standard method. The kepone was extracted from a 1 L seawater sample by 50 mL dichloromethane. Sulfuric acid was used to remove the interference materials co-extracted from the sample. After cleanup, the extract was dissolved in 1% (v/v) methanol/hexane solvent and analyzed by GC-ECD. In the linear range from 5 microg/L to 100 microg/L of kepone, the correlation coefficient was 0.998 9. The average spiked recoveries were 81% - 108% with the relative standard deviations (RSDs) of 1.2% -5.1% (n = 6). The detection limit was 0.6 ng/L. This method shows good extraction efficiency, high sensitivity and good reproducibility, and is suitable for the determination of kepone in seawater.