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

• Published in: Journal of Chromatography A 2019-06, Vol.1595, p.19-27
• Main Authors: He, Yifeng, He, Man, Nan, Kai, Cao, Rongkai, Chen, Beibei, Hu, Bin
• Format: Article
• Language: English
• Subjects: Environmental samples; HPLC-ICP-MS; Magnetic solid phase extraction; Mercury speciation; Sulfur-containing functional magnetic polymer
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2019.02.050

•1,2-ethanedithiol functionalized magnetic polymer material was fabricated.•The prepared sulfur functionalized MNPs has high adsorption capacity towards Hg.•The MSPE-HPLC-ICP-MS was proposed for mercury speciation in environmental samples.•The method has low LODs, high enrichment factors, and fast analytical speed. 1,2-Ethanedithiol was firstly involved in preparing sulfur-containing functional magnetic polymer material of Fe3O4@SiO2@ glycidyl methacrylate (GMA)-S-SH. The prepared Fe3O4@SiO2@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 Fe3O4@SiO2@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 Hg2+, methylmercury (MeHg+) and phenylmercury (PhHg+). Variables affecting the simultaneous extraction of three target mercury species were investigated. It was found that Hg2+, 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−1 nitric acid and 4% thiocarbamide in 2 min. The developed method has high actual enrichment factors of 367, 380, 329-fold for Hg2+, MeHg+ and PhHg+, respectively. The detection limits were 0.40, 0.49 and 1.4 ng L−1 with the relative standard deviations (n = 5, inter-day) of 7.4, 8.1 and 8.3% for Hg2+, 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.