Ouangpipat Winai, Lelasattarathkul Tapparath, Dongduen Churairat, Liawruangrath Saisunee
Department of Chemical Technology, Rajamangala Institute of Technology, Bangkok Technical Campus, Bangkok, Thailand.
Talanta. 2003 Nov 12;61(4):455-64. doi: 10.1016/S0039-9140(03)00316-3.
The present work describes the development and application of a carbon paste electrode modified by treated-Pennisetum setosum for the determination of lead(II) by anodic stripping differential pulse voltammetry. Most experiments were performed using the preconcentration/voltammetry/regeneration scheme. The resulting modified electrode offers a preferential uptake of lead(II) from solutions. Operational conditions, such as percentage treated-Pennisetum loading in the carbon paste, pH of electrolyte solution, ionic strength, preconcentration time, voltammetric waveform and interference are characterized and optimized to allow quantitative determination of lead. The electrode surface can be regenerated by immersing the modified electrode in 0.05 mol l(-1) hydrochloric acid for 2 min. For the measurement step, the optimum conditions were acetate buffer pH 5.0 and 0.60 ionic strength with the preconcentration time of 5 min. The modified electrode contained 10% (w/w) treated-Pennisetum. The detection limit (3sigma) was 0.01 mg l(-1) Pb(II). For 16 preconcentration/measurement/renewal cycles, the responses could be reproduced with a 5.39% relative standard deviation. This method has been be successfully applied to the determination of lead(II) in natural water samples using standard addition method.
本工作描述了一种经处理的狼尾草修饰的碳糊电极的研制及其在阳极溶出微分脉冲伏安法测定铅（II）中的应用。大多数实验采用预富集/伏安法/再生方案进行。所得修饰电极对溶液中的铅（II）具有优先吸附作用。对诸如碳糊中处理过的狼尾草负载百分比、电解质溶液的pH值、离子强度、预富集时间、伏安波形和干扰等操作条件进行了表征和优化，以实现铅的定量测定。将修饰电极浸入0.05 mol l(-1)盐酸中2分钟可使电极表面再生。对于测量步骤，最佳条件为醋酸盐缓冲液pH 5.0、离子强度0.60，预富集时间5分钟。修饰电极含有10%（w/w）处理过的狼尾草。检测限（3σ）为0.01 mg l(-1) Pb（II）。对于16个预富集/测量/更新循环，响应的相对标准偏差为5.39%，可重现。该方法已成功应用于采用标准加入法测定天然水样中的铅（II）。
