Trace level monitoring of pesticides in water samples using fatty acid coated magnetic nanoparticles prior to GC-MS

Palmitic acid coated magnetic nanoparticles (PA-Fe3O4 MNPs) were employed in a simple and fast solid phase extraction procedure for the preconcentration of pesticides prior to GC-MS determination. The main factors influencing extraction efficiency including surfactant amount, sample pH, extraction time, desorption conditions and concentration of nanoparticles were optimized. Under the optimized conditions, a preconcentration factor of 1000 was achieved. Limits of detection and quantification in the range of 20-30 ng L-1 and 60-80 ng L-1, respectively, were obtained for the proposed pesticides which include diazinon, pirimiphos methyl, aldrin-R, fenthion, chlorpyrifos, dicofol, triadimefon, heptachlor-epoxide (Cis), fipronil, triadimenol, triflumizole, O,P-DDE, butachlor, pretilachlor, P,P-DDE, oxadiazon, O,P-DDD, buprofezin, P,P-DDD, O,P-DDT, ethion, benalaxyl, endosulfan-sulfate, propiconazol I, propiconazol II, tebuconazole, bifenthrin, methoxychlor, fenpropathrin, landa cyhalothrin, fenarimol, bitertanol, permethrine I, permethrine II, prochloraz, fenbuconazole, cypermethrin-alpha and esfenvalerate. In order to investigate the matrix effect on the method efficiency, it was used to determine the mentioned pesticides in real environmental water samples including tap, bottled drinking and pool water. The results obtained were in agreement with those obtained by a classical SPE method for the determination of pesticides.