Magnetic solid-phase extraction using sulfur-containing functional magnetic polymer for high-performance liquid chromatography-inductively coupled plasma-mass spectrometric speciation of mercury in environmental samples.

1,2-Ethanedithiol was firstly involved in preparing sulfur-containing functional magnetic polymer material of FeO@SiO@ glycidyl methacrylate (GMA)-S-SH. The prepared FeO@SiO@GMA-S-SH magnetic nanoparticles (MNPs) show better adsorption capacity and adsorption/desorption dynamics for mercury species than other -SH functional materials due to the high affinity of both thioether and thiol group towards mercury. A new method of magnetic solid phase extraction (MSPE) using FeO@SiO@GMA-S-SH as sorbents combined with high performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the analysis of trace Hg, methylmercury (MeHg) and phenylmercury (PhHg). Variables affecting the simultaneous extraction of three target mercury species were investigated. It was found that Hg, MeHg and PhHg in 200 mL of water sample could be quantitatively adsorbed within 5 min and eluted by 0.5 mL 0.1 mol L nitric acid and 4% thiocarbamide in 2 min. The developed method has high actual enrichment factors of 367, 380, 329-fold for Hg, MeHg and PhHg, respectively. The detection limits were 0.40, 0.49 and 1.4 ng L with the relative standard deviations (n = 5, inter-day) of 7.4, 8.1 and 8.3% for Hg, MeHg and PhHg, respectively. The accuracy of the method was validated by the analysis of the Certified Reference Materials of GSS-11 soil, GSS-13 soil, GSB21 rice and DORM-2 fish. The established method was successfully used for the mercury speciation in farmland water, soil and rice samples collected from Wanshan, China, and satisfactory recoveries (84.3-116%) were obtained for the spiked samples.