Determination of Organochlorine Pesticides in Water using Solid-Phase Extraction

An analytical method was developed for GC/MS monitoring of 22 organochlorine pesticides in water using 47mm SDB-XC bond disks. The sample was passed through the disk under vacuum. The pesticides trapped in disk was extracted with acetone and hexane by ultrasonication. The extracted solution was concentrated to 5ml and cleaned up by Sep-Pak silica (690mg) and then analysed by GC/MS. The recoveries of pesticides from river water were in the range 80-104% except for HCB, Aldrin, and Endrin aldehyde. The recoveries were estimated by calibration standard solution (blank) which was prepared with n-hexane obtained through the extraction step using SDB-XC. The calibration standard solution (blank) was devised for the standard solution to compensate the matrices effect and to decrease rate of decomposition of DDT and Endrin in the injection port of GC.