Magnetic solid-phase extraction of pesticides in environmental water samples Fe3O4@SiO2@C18 nanoparticles coupled to GC-MS determination

A rapid magnetic solid-phase extraction (MSPE) method coupled to Gas Chromatography-Mass Spectrometry (GC-MS) was developed for the simultaneous extraction of ten pesticides belonging to various categories (insecticides, herbicides and fungicides) in environmental water samples. The magnetic Fe3O4@SiO2@C18 nanoparticles were synthesized by coprecipitation of Fe2+ and Fe3+ ions, at alkaline conditions, under hydrothermal treatment and used as adsorbents of MSPE. The proposed method is optimized by means of experimental design and response surface methodology. Several parameters influencing MSPE efficiency were investigated. The most important were the amount of the sorbent and the extraction time. Under optimal conditions, the MSPE/GC-MS method presented fast simple separation and analysis, and excellent linearity in the range of 6.4–5000.0 ng/L, with coefficients of determination (R2) higher than 0.9901 for all compounds. Moreover, the performance of the MSPE method was compared to a conventional SPE and the MSPE method was comparable. Finally, the optimized method was applied in a case-control study carried out in Rivers Aliakmonas, Loudias and Axios (Macedonia Region-North Greece). The most frequently detected compounds were atrazine, methyl-parathion, chlorpyriphos and irgarol. The magnetic Fe3O4@SiO2@C18 composites based MSPE method proved promising for convenient and efficient determination of pesticides in environmental water samples.