Sampling and analysis of pesticides in the gas phase of air: method validation using a volatilization chamber

This study evaluated the efficiency of Tenax (R) resin to sample the pesticides, atrazine, chlorpyrifos, alpha,beta-endosulfan, metolachlor and trifluralin, from contaminated air in a volatilization chamber. The air contamination was performed by adding pesticide masses in the range of 100-750 ng in a chamber at an air flow rate of 2.60 L min(-1) at 35 degrees C for 12 h. After volatilization, the pesticides followed the airflow toward the cartridges packed with two sequential sections of Tenax (R) resin, separated by glass wool. In this apparatus, the sampling efficiency remained between 82 and 119%, with RSD% lower than 14%. The method quantitation limit (MQL) was 53.4 ng m(-3) for all studied analytes. Comparative trials with the resin XAD (R)-2 showed the sampling efficiency between 83 and 92%, with CV less than 10%. The volatilization chamber also allowed the evaluation of the volatilization profile of each analyte and helped in the sampling cartridge setting, in order to prevent the breakthrough effect.