Magnetic solid-phase extraction of triazine herbicides from rice using metal-organic framework MIL-101(Cr) functionalized magnetic particles

The metal-organic framework (MOF) functionalized magnetic graphene oxide/mesoporous silica composites (Fe₃O₄@SiO₂-GO/MIL-101(Cr)) were synthesized and utilized as magnetic solid-phase extraction (MSPE) adsorbent for the extraction of seven triazine herbicides (terbuthylazine, secbumeton, terbumeton, atraton, atrazine, prometon and trietazine) in rice samples. Several experimental parameters, including type and volume of extraction solvent, amount of MIL-101(Cr), extraction time, volume of desorption solvent and desorption time were investigated and optimized. The limits of detection (LODs) of seven triazine herbicides obtained by using the proposed MSPE method combined with high performance liquid chromatography (HPLC) were in the range of 0.010–0.080 µg kg⁻¹. The recoveries of the triazine herbicides in spiked rice samples ranged from of 83.9–103.5% with the relative standard deviations lower than 8.7%. The intra and inter-day (n = 6) precisions for all triazine herbicides at the spiked level of 100.0 µg kg⁻¹ were 1.4–5.9% and 2.6–7.8%, respectively.