DEVELOPMENT AND VALIDATION OF AN ANALYTICAL METHOD FOR NALED AND DICHLORVOS IN AIR

A new gas chromatographic method for analysis of the thio organophosph ate pesticide naled and its transformation product dichlorvos (DDVP) w as developed and validated. Naled and DDVP in air were trapped on XAD- 4 resin. The pesticides were recovered from the resin with ethyl aceta te. Ethyl acetate extract was analyzed for naled and DDVP by using a g as chromatograph equipped with a DB-5 Megabore capillary column and a nitrogen-phosphorus detector. The limits of quantitation for naled and DDVP were 0.05 and 0.10 mu g/sample, respectively. Naled and DDVP tra pped on the resin were stable over 21 days at -20 degrees C. Trapping efficiencies of naled and DDVP in the air samples were 74.5 +/- 3.5% a nd 49.7 +/- 3.3%, respectively. The newly developed method showed exce llent results for the air samples collected at the application sites. Maximum observed concentrations of naled and DDVP at the application s ites were 6.30 and 0.99 mu g/m(3), respectively.