A rapid low-consuming solvent extraction procedure for simultaneous determination of 34 multiclass pesticides associated to respirable atmospheric particulate matter (PM2.5) by GC-MS

A miniaturized and low-consuming solvent extraction procedure has been developed for the simultaneous determination of 34 multiclass pesticides in PM2.5 samples, using sample masses as low as 321 mu g. A central composite design was applied in order to establish the optimal extraction conditions: the solid-liquid extraction was done under sonication using 500 mu L. of a solvent mix 70/30 acetonitrile/ethyl acetate and an extraction time of 17 min at 39 degrees C. It was followed by injection in a GC-MS system. Recoveries ranged from 72.1% (endrin aldehyde) to 120% (sulfotep) with RSD <= 20% for most of pesticides. The method accuracy was assessed by determinations of organochlorine pesticides such as 4,4'-DDT, 4,4'-DDE and 4,4'-DDD in NIST SRM 1649b. PM2.5 samples were collected in Salvador city, State of Bahia-Brazil. 25 pesticides were successfully identified and quantified, among them organophosphates prohibited by European Union and some banned organochlorine. The average concentrations ranged from 0.88 pg m(-3) (aldrin) to 255 pg m(-3) (endrin aldehyde). Malathion, chlorpyrifos, 4,4'-DDE, endrin aldehyde, lambda-cyhalothrin and permethrin were detected with frequencies above 50%. This procedure was found to be comprehensive, precise, accurate and suitable to be employed for determination of pesticides associated to respirable atmospheric particulate matter. (C) 2018 Elsevier B.V. All rights reserved.