Ghoneim M M, Hassanein A M, Hammam E, Beltagi A M
Chemistry Department, Faculty of Science, Tanta University, Egypt.
Fresenius J Anal Chem. 2000 Jun;367(4):378-83. doi: 10.1007/s002160000410.
A highly sensitive and selective voltammetric procedure is described for the simultaneous determination of eleven elements (Cd, Pb, Cu, Sb, Bi, Se, Zn, Mn, Ni, Co and Fe) in water samples. Firstly, differential pulse anodic stripping voltammetry (DPASV) with a hanging mercury drop electrode (HMDE) is used for the direct simultaneous determination of Cd, Pb, Cu, Sb and Bi in 0.1 M HCI solution (pH = 1) containing 2 M NaCl. Then, differential pulse cathodic stripping voltammetry (DPCSV) is used for the determination of Se in the same solution. Zn is subsequently determined by DPASV after raising the pH of the same solution to pH 4. Next, the pH of the medium is raised to pH 8.5 by adding NH3/NH4Cl buffer solution for the determination of Mn by DPASV. Ni and Co are determined in the same solution by differential pulse adsorptive stripping voltammetry (DPAdSV) after adding DMG (1 x 10(-4) M). Finally, 1 x 10(-5) M 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) is added to the solution for the determination of Fe by DPAdSV. The optimal conditions are described. Relative standard deviations and relative errors are calculated for the eleven elements at three different concentration levels. The lower detection limits for the investigated elements range from 1.11 x 10(-10) to 1.05 x 10(-9)M, depending on the element determined. The proposed analysis scheme was applied for the determination of these eleven elements in some ground water samples.
本文描述了一种高灵敏度和高选择性的伏安法，用于同时测定水样中的11种元素（镉、铅、铜、锑、铋、硒、锌、锰、镍、钴和铁）。首先，使用悬汞滴电极（HMDE）的差分脉冲阳极溶出伏安法（DPASV），在含有2 M氯化钠的0.1 M盐酸溶液（pH = 1）中直接同时测定镉、铅、铜、锑和铋。然后，使用差分脉冲阴极溶出伏安法（DPCSV）测定同一溶液中的硒。随后，将同一溶液的pH值提高到4后，用DPASV测定锌。接下来，加入氨/氯化铵缓冲溶液将介质的pH值提高到8.5，用DPASV测定锰。加入二甲基乙二醛肟（1×10⁻⁴ M）后，用差分脉冲吸附溶出伏安法（DPAdSV）在同一溶液中测定镍和钴。最后，向溶液中加入1×10⁻⁵ M 2-（5-溴-2-吡啶偶氮）-5-二乙氨基苯酚（5-Br-PADAP），用DPAdSV测定铁。描述了最佳条件。计算了三种不同浓度水平下11种元素的相对标准偏差和相对误差。所研究元素的最低检测限范围为1.11×10⁻¹⁰至1.05×10⁻⁹ M，具体取决于所测定的元素。所提出的分析方案应用于一些地下水样中这11种元素的测定。
