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

Abstract

This study evaluated the efficiency of Tenax® resin to sample the pesticides, atrazine, chlorpyrifos, α,β-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 °C for 12 h. After volatilization, the pesticides followed the airflow toward the cartridges packed with two sequential sections of Tenax® 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®-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.