Selection of Extraction Solvents with Based on Solubility Parameters for Extracting the Organochlorine Pesticides in Soils

The solubility parameters,including dispersion coefficient(δ d ),polarity(δ p )and hydrogen bonding(δ h ),of extraction solvents(including hexane,dichloromethane,hexane-methanol(4∶1by volume,the same below),hexane-acetone(1∶1),hexane-dichloromethane(1∶1))and organochlorine pesticides were estimated using a group contribution method,and then used to prediction the optimal extraction solvents to exˉtract the typical organochlorine pesticides from the Jiangxi red soil.The solvents such as hexane-methanol(4∶1)and hexane-acetone(1∶1)were determined selected as ideal extraction solvents to extract o,p′- DDT,o,p′-DDE and o,p′-DDD with high recoveries(82%).Besides,these solvents were used to extractα-endosulfan,endrin and HCB with the reliable recoveries(75).The results obtained with ultrasonic extracˉtion were in accordance with the estimated predictions from conclusion by the solubility parameters.