Rapid GC-MS Determination of BHC and DDT Residues in Soil After Purification by On-line Gel Permeation Chromatography

Rapid GC-MS determination of residual amounts of 8 isomers or homologues of BHC and DDT in soil was achieved by separation with accelerated solvent extraction (ASE) and purification with on-line gel permeation chromatography (GPC).Mixed solvent of dichloromethane and acetone (1 to 1 by vol.) was used as the extraction solvent in ASE,and the extracts obtained were combined and evaporated to near dryness.The residue was taken up with acetone,diluted to 10 mL and used for GC-MS analysis after purification by the on-line GPC.The mode of SIM was used in the MS-detection.Qualitative analysis was performed based on the retention time and characteristic ions,and quantitative analysis was carried out by the external standard method.Linear relationships between values of peak area and concentration of the 8 pesticides were obtained in the same range of 0.02 to 0.4 mg·L-1,with their detection limits (3S/N) in the range of 0.014 7-0.078 3 μg·kg-1.Results of recovery test were found in the range from 101.4% to 129.5%.