Application of Disk-format Solid Phase Extraction to Pesticide Analysis

A membrane extraction disk (EmporeTMExtraction Disks SDB-XC) was evaluated as a solid phase extraction (SPE) medium for the isolation and the trace enrichment of pesticides from water samples. Reagent water, tap water and natural waters spiked with 32 pesticides at the concentration of 0.005mg/l were extracted with the SPE disk prior to the GC/MS determination of the pesticides. For most of the pesticides, the percent recoveries from reagent water were in the range from 90 to 110% with the coefficient of variation below 5% on the elution by dichloromethane, acetone, ethyl acetate or methyl t-butyl ether. The time needed to extract 200ml sample was about 1 minute for the reagent water and the tap water. In the case of natural waters, the extraction time were ranged 1-12min depending on the suspended solids in the samples. The extraction time over 10 minutes could be fairly reduced by putting filter aids on the top of the disk.