Stripping Voltammetry Of Trace Detection Of Mercury Using Boron-Doped Diamond Electrodes

Hg in surface water is mostly from the industry waste water made by noble metal smelt, machine produce, chlorine alkali chemistry, pharmacy and so on. Hg is a substance with high empoison. The maximum permissible concentration (MPC) of mercury in drinking water as set by the EPA is 2ppb. In comparison to other metals, mercury has a very low permissible level. So, it is very important to measure Hg in surface water.Current methods used for mercury detection includes coldvapor atomic fluorescence spectrometry (CV-AFS), cold-vapor atomic absorption spectrometry (CV-AAS), and inductively coupled plasma-mass spectrometry (ICPMS). These methods require relatively large sample volumes for analysis and considerable time between sample collection and analysis. Therefore, these techniques are not suitable for on-line monitoring. DPV, which is used to measure Hg in surface water, has many characteristics such as good anti-jamming capability , high delicacy, speediness, low cost. Its relatively standard error is 5%～7%, and it is the same with measuring Hg in surface water and waste water.The present article introduces the good capability of diamond film electronic, the imperilment caused by Hg to the body, and several kinds of methods to examine it. Then this article introduces how to produce BDD, taking up with improving on the technology of producing BDD, improving the technics, producing high quality BDD. In the end, we studies the good electrochemistry characters of BDD, in order to using it in examining Hg. Measuring title Hg separately by BDD and carbon, we find that although BDD and carbon can also measuring the apex of Hg in high concentration solution, in low concentration only BDD can measure the apex of Hg and carbon can not. At the same time, we fide that the solution can seriously impact the apices electricity and apices current of metal ionic, the experiment shows that in 2.0mol/L Hcl and 1.5mol/L KCl solution, Hg has good apices electricity and good apices current. But because of the exist of cl ionic, the stable and reproducible of electrode are influenced. In order to avoid this problem, we made BDD together with gold co-deposition, because that the important observation in these experiments is the formation of highly insoluble product Hg2Cl2 (calomel), which can affect the reproducibility of the experiment unless the calomel is cleaned from the surface. As we know, gold is an excellent metal that forms amalgam with mercury. Therefore, the choice of gold addition can improve the sensitivity and reproducibility for the detection of mercury. Experiments with gold co-deposition indicated excellent reproducible stripping peaks for mercury.