Magnetic Nanoparticle-Based Micro-Solid Phase Extraction and GC-MS Determination of Oxadiargyl in Aqueous Samples

A new facile, rapid, inexpensive, and sensitive method based on magnetic micro-solid phase extraction (M-mu-SPE) coupled to gas chromatography-mass spectrometry (GC-MS) was developed for determination of the herbicide oxadiargyl in environmental water samples. The feasibility of employing non-modified magnetic nanoparticles (MNPs) as sorbent was examined and applied to perform the extraction process. Influential parameters affecting the extraction efficiency along with desorption conditions were investigated and optimized. The limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) of the method under optimized conditions were 0.005 and 0.030 ng mL(-1), respectively. The relative standard deviations (RSD) (n = 3) at a concentration of 0.10 ng mL(-1) was 11%. The calibration curve of oxadiargyl showed linearity in the range of 0.050-0.50 ng mL(-1). The developed method was successfully applied to the extraction of oxadiargyl from spiked tap water and Zayande-Rood River water samples and the relative recoveries of 98 and 94% were obtained, respectively.