Magnetic Solid-Phase Extraction Based on Amino-functionalized Magnetic Starch for Analysis of Organochlorine...

A magnetic starch modified with 3,5-diaminobenzoic acid and 3-aminopropyltriethoxysilane (Fe-starch@DABA-APTES) was synthesized and applied as adsorbent for the extraction of organochlorine pesticides (OCPs). Magnetic solid-phase extraction was developed using 75 mg of the sorbent and 15 mL of a sample solution. Extraction was conducted on a vortex mixer for 40 s. The adsorbent was collected using an external magnet before eluting the analytes using 0.5 mL of methanol. Quantification of the analytes was performed using gas chromatography with a micro-electron capture detector. The linearity was obtained for the studied OCPs in the range between 0.01 - 2.00 μg L^-1. The detection and quantification limits were obtained in ranges of 0.5 - 4.0 and 1.5 - 15.0 ng L^-1, respectively, with enrichment factors of up to 39. The precision in terms of the intra- and inter-day relative standard deviations (RSDs) were below 4.75, and 9.25%, respectively. The developed method has been applied in natural water and agricultural product samples. The recoveries ranged between 59.83 - 132.67% (RSDs < 10.73%).