Adsorption/thermal desorption-GC/MS for the analysis of pesticides in the atmosphere

An analytical methodology using Automatic Thermal Desorption (ATD) and GC/M S was developed for the determination of the pesticides alachlor, atrazine, captan, formothion, lindane and phosalone in atmospheric samples. This met hodology was developed to evaluate the atmospheric contamination by pestici des during treatments and by post-application. Atmospheric samples were col lected by using (4 i.d. x 89 mm) stainless steel sampling tubes containing 125 mg of adsorbents at a flow rate of 80 mi min(-1). Different types of ad sorbents were tested for their ability to efficiently trap pesticides under study: Tenax TA, Carbopack Y, Carbopack B, Carbotrap, Carboxen, Chromosorb 106 and XAD-4. Results of experiment show that Tenax gives the better resu lts for all the pesticides used but the use of the thermal-desorption metho d, especially for pesticides with low volatility and/or poor thermal stabil ity presents some difficulties. This method was validated by the analysis o f the contamination of atmosphere, through volatilisation by post-applicati on processes, of atrazine in a parcel of 1 ha. (C) 1999 Elsevier Science Lt d. All rights reserved.