Extraction and preconcentration of trace amounts of diazinon and fenitrothion from environmental water by magnetite octadecylsilane nanoparticles

In this study, a method for extraction and preconcentration trace amounts of organophosphorus pesticides (OPPs) in environmental water was developed using magnetic solid phase extraction (magnetic-SPE) followed by high performance liquid chromatography (HPLC) with UV detection. Magnetite octadecylsilane nanoparticles were synthesized and characterized by X-ray diffraction, FTIR spectroscopy, vibrating sample magnetometry and scanning electron microscopy. These nanoparticles were applied for extraction and preconcentration of OPPs (residues of diazinon and fenitrothion, which are the most-widely used for pest control in Iran) in environmental water samples at low ng mL(-1) concentration as magnetic-SPE adsorbent. The extraction conditions and efficiency of the nanoparticles for OPPs were investigated. The method was evaluated according to the reproducibility, enrichment factor, linearity range and limits of detection. Under optimized conditions, method showed good linearity between 0.03-0.06 and 30 ng mL(-1) with regression coefficients (R-2) of 0.997 and 0.998. Limits of detection were 0.019 and 0.014 ng mL(-1). The enrichment factors of this method were 172 and 184 and the analysis yielded good reproducibility with the RSD values 7.2% and 5.4% at the 10 ng mL(-1) level (n = 5) for diazinon and fenitrothion, respectively. Determination of OPPs can be easily carried out with this fast, accurate, sensitive and simple method procedure. (c) 2012 Elsevier B.V. All rights reserved.