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

Abstract

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 321μg. A central composite design was applied in order to establish the optimal extraction conditions: the solid-liquid extraction was done under sonication using 500μL of a solvent mix 70/30 acetonitrile/ethyl acetate and an extraction time of 17min at 39°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 0.88pgm−3 (aldrin) to 255pgm−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.