【作者】 沈锋英；

【导师】 常明；

【作者基本信息】 天津理工大学 ， 物理电子学， 2008， 硕士

【摘要】 重金属离子在环境化学与公众健康中的重要作用是已被人们广泛认知。在这些重金属离子中,其中Pb²⁺最为人们关注,这是因为铅的化合物具有高度的毒性,并容易在各种生物体中积累。而且铅经常用来作为供水管道的材料,因此自来水与铅管有长时间的接触（比如说,一晚上）,从而自来水中含有较高量的铅。基于这些原因,在自来水中检测Pb²⁺的浓度变得越来越重要。目前主要利用电感耦合等离子体质谱仪（ICP-MS）或原子吸附法来检测在饮用水中的铅含量,并且采用离子色谱仪也可以得到比较令人满意的检测。虽然这些方法都具有高灵敏度,但它们不适合广泛使用,因为它们需要昂贵和笨重的检测设备。阳极溶出伏安法本来就是一种非常灵敏的检测方法,而且使用其来痕量分析重金属已经在很多实验中得到证实。几种ASV仪器已成功的用于铅检测,但它们中的大多数工作电极都使用滴汞电极,或汞膜电极。然而,考虑到这些电极都具有明显毒性的,所以目前正在努力寻求用于铅检测的无汞分析仪。可导性金刚石是一种在电化学分析中引起人们广泛关注的电极材料,由于它显著的电化学特性:在水溶液中有宽的电势窗口,低背景电流,在反应中长期的稳定性和对溶解氧而言低敏感度。多晶金刚石的这些独特的特性,和它的弱吸附性,使得这种材料非常适合利用溶出伏安法来检测自来水中的Pb²⁺。因此,将金刚石膜电极的制备、ASV法检测自来水中Pb²⁺的相结合,不仅拓宽了金刚石膜的应用领域,具有较好的理论意义,同时也使得铅检测设备简单且易行成本相对降低,具有很好的实际效用。本文首先介绍了铅检测的几种方法,并着重介绍了伏安分析法的过程和它的几种工作电极。然后介绍了金刚石膜电极的制备与表征,包括探索其成膜影响因素、工艺参数等。最后研究金刚石膜优异的电化学特性,将金刚石膜电极应用于在自来水中检测Pb²⁺。通过在掺硼金刚石电极（BDD）上利用线性扫描阳极溶出伏安法来检测自来水中痕量Pb²⁺。相对于其他电极材料而言低检测限（2 nM）是掺硼金刚石电极的一个优势,并在实验中发现,当支持电解液处于低PH值时,且在自来水水中存在一定浓度的Cu²⁺时,在很大程度上并不影响Pb²⁺的检测。这些实验结果表明,在BDD电极上利用阳极溶出伏安法来检测在自来水中的痕量Pb²⁺是一种较好的无汞测量法。且得到的将自来水作为实际检测样品时检测铅得到的检测结果与电感耦合等离子体质谱仪（ICP-MS）检测结果非常吻合。这表明了在掺硼金刚石电极（BDD）上利用线性扫描阳极溶出伏安法来检测痕量Pb²⁺是一种切实可行的具有分析效用的方法。更多还原

【Abstract】 The important role that heavy transition metals play in environmental chemistry and public health is widely recognized. Among these metal ions, Pb²⁺ is of great concern both because of the high toxicity of its compounds, and accumulation in various organisms. Furthermore, lead is frequently used as a material for water supply pipes, and tap water that has been in contact with a lead pipe for a long time （e.g., overnight） can contain relatively high amounts of lead. For these reasons, it has become increasingly important to monitor lead in drinking water.At present, lead in tap water is mainly measured by inductively coupled plasma-mass spectrometry （ICP-MS） or atomic adsorption, but promising results have been also obtained by using ion chromatography techniques. Although these methods are highly sensitive, they are not suitable for extensive use because they require expensive and cumbersome equipment.Anodic stripping voltammetry （ASV） is inherently a very sensitive method and its use for trace analysis of heavy metals is well substantiated. Several techniques of ASV have been successfully employed for lead detection, but most of them involved either hanging mercury drop electrodes, or mercury film electrodes. Nevertheless, due to obvious toxicity considerations, mercury-free analytical systems for lead determination are currently sought. Conductive diamond represents an electrode material that has attracted great interest in electroanalysis, due to its outstanding electrochemical features: wide potential window in aqueous solutions, low background current, long-term stability of the response and low sensitivity to dissolved oxygen. These unique properties of the polycrystalline diamond, together with its extreme robustness, strongly recommend this material as very well suited for stripping voltammetry analysis of Pb²⁺ in tap water.Therefore, if we combine the diamond film electrode preparation with detecting trace levels of lead by linear-sweep anodic stripping voltammetry. It can not only advance energy utilized efficiency, but also simple and reduce the cost,have practical analytical utility.The present article introduces the relative knowledge about different methods of detecting trace levels of lead, That emphasizes the process of the ASV and the working electrode. Then, it introduces the relevant knowledge of diamond film electrode preparation and token, including exploring its growth influence, craftwork parameter etc. Lastly, it studies the electrochemistry character of diamond film, in order to put diamond film electrode in analysis of Pb²⁺ in tap water. Boron-doped diamond （BDD） electrodes were used to investigate the possibility of detecting trace levels of lead by linear-sweep anodic stripping voltammetry. The low limit of detection （2 nM） is an advantage compared to other electrode materials, and it was found that at low PH values, copper concentrations that are usually present in drinking water do not affect to a large extent the detection of lead. These findings recommend anodic stripping voltammetry at the BDD electrodes as a suitable mercury-free method for the determination of trace levels of lead in drinking water. The results obtained for the lead detection in tap water real samples are in excellent agreement with those found by inductively coupled plasma-mass spectrometry （ICP-MS）, demonstrating the practical analytical utility of the method.更多还原