博彩平台

Junling Zhang^a, Zengwei Zhu^a, Junwei Di^a, Yumei Long^{a, b} * （龙玉梅）， Weifeng Li^a, *（李伟峰）,Yifeng Tu^a

^a College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, PR China

^b The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, PR China

Electrochimica Acta ,Volume 186, 20 December 2015, Pages 192–200

This work reports a sensitive sensor for the electrochemical determination of trace mercury (Hg²⁺) by employing ultrathin graphitic carbon nitride (utg-C₃N₄) nanosheet as enhanced sensing platform. The utg-C₃N₄ nanosheets were obtained by exfoliating the bulk g-C₃N₄, which was synthesized via a thermal polycondensation process. The as-prepared samples were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM), which confirmed graphite-like structure with thickness of about 8 nm. The g-C₃N₄ nanosheets can be easily attached on the surface of glassy carbon (GC) electrode free of any film-forming agent. It was found that Utg-C₃N₄ modified GC electrode showed enhanced electrochemical response to Hg²⁺ in comparison with bulk g-C₃N₄, which could be ascribed to the strong affinity between utg-C₃N₄ and Hg²⁺ through its <img border="0" alt="single bond" src="//cdn.els-cdn.com/sd/entities/sbnd" class="glyphImg">NH and <img border="0" alt="single bond" src="//cdn.els-cdn.com/sd/entities/sbnd" class="glyphImg">NH₂ groups. This allows detection of Hg²⁺ in aqueous solutions with high sensitivity and selectivity. Under the optimized experimental conditions, the anodic stripping voltammetric (ASV) currents are linearly responsible to Hg²⁺ concentrations in the range of 0.1–15 μg/L with a detection limit of 0.023 μg/L (S/N = 3). The sensitivity of the as-constructed sensor is about 6.8 μA(μg/L)⁻¹ cm⁻². In addition, the proposed sensor was applied in determining Hg²⁺ in practical samples and the results are comparable to those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) method.