Development of determination method for carbofuran and oxydemeton-methyl in ambient air

A gas chromatographic method was developed for the determination of carbofuran and oxydemeton-methyl (ODM) as well as ODM's potential transformation product, deoxydemeton-methyl (DODM), in ambient air. The chemicals were trapped using XAD-4 resin and recovered with an organic solvent. The extraction efficiencies of carbofuran, ODM, and DODM from a XAD-4 resin with ethyl acetate were near 100%. A trapping efficiency study for ODM and DODM demonstrated that both compounds were relatively nonvolatile at 35 +/- 5 degrees C. Using the method developed, air sampling was conducted at agricultural sites in California where carbofuran, ODM, and DODM have been applied. The highest amount of carbofuran found in the ambient air samples was 2.1 mg (ca. 97 pg/L of air). However, none of the samples collected from ambient air had a sufficient amount of ODM or DODM for the limit of quantitation (0.05 mg).