Synthesis of MoS2 nanosheets for mercury speciation analysis by HPLC-UV-HG-AFS

Mercury species have aroused wide concern in the past several decades due to their high toxicity. However, it is still difficult to detect ultra-trace mercury species due to their biochemical transformation in complex samples. To establish a simpler and more sensitive method for pre-concentration and determination of trace mercury species, molybdenum disulfide (MoS 2 ) nanosheets with sulfur-rich characteristics and enlarged interlayer spacing were prepared by a hydrothermal method coupled with a sonication-assisted liquid exfoliation method and acted as solid-phase extraction adsorbent. The nano-MoS 2 had high adsorption capacity, fast adsorption rate and excellent selectivity towards mercury ions (Hg 2+ ), methyl mercury (MeHg + ) and ethyl mercury (EtHg + ) in a wide pH range and complex matrices. And it could be easily regenerated by 4 mol L −1 HCl and reused several times. After optimizing HPLC-UV-HG-AFS conditions, a great linearity (1.0-10.0 μg L −1 , R 2 = 0.999 for Hg 2+ , MeHg + and EtHg + ), lower detection limits (0.017, 0.037 and 0.021 ng mL −1 for Hg 2+ , MeHg + and EtHg + , respectively), relative standard deviations (