Determination of Endosulfan and Its Metabolites in Export Loach by GC-MS with Negative Ion Chemical Ionization

A method of GC-MS with negative ion chemical ionization was proposed for determination of endosulfan and its metabolite (endosulfan sulfate). The effects of rapid solvent extraction, homogeneous extraction and oscillation extraction were examined. The interference of oils in the samples was eliminated effectively by solid-phase extraction purification combined with centrifugation method. The detection time was effectively shortened by optimizing the instrument conditions. The linearity range of the mass concentration of endosulfan and its metabolites was 0.005-0.400 mg·L-1 with detection limits in the range of 0.04-0.05 μg·kg-1 and lower limits of determination in the range of 0.12-0.18 μg·kg-1. Recovery rates measured by standard addition method were in the range of 89.1%-100%, and RSD (n=6) was in the range of 2.9%-8.3%. The method was suitable for rapid batch detection of export loach.