An improved colorimetric determination of lead(II) in the presence of nonionic surfactant
An improved colorimetric determination of lead(II) in the presence of nonionic surfactant
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DOI：
10.2116/analsci.22.1227
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发表时间：
2006-09-01
影响因子：
1.6
通讯作者：
Akl, Magda Ali
中科院分区：
文献类型：
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作者：
Akl, Magda Ali
菲醌单苯基缩氨基硫脲（PPT）是一种优良的显色剂，在水溶液中与铅（Ⅱ）形成微溶的络合物。为了确定这种金属离子，必须进行繁琐且耗时的分离技术，例如液-液萃取。然而，Pb（II）-PPT配合物可以方便地测定紫外-可见（UV-Vis）分光光度法在520 nm处的吐温80胶束介质中，具有聚氧乙烯基团。将pH值、PPT浓度和稳定性等条件调节至最佳值后，比较了吐温80胶束介质和氯仿介质中Pb（II）离子的灵敏度。结果表明，在吐温80胶束介质中，铅（Ⅱ）的灵敏度比在氯仿介质中高。研究了不同阳离子和阴离子对测定的干扰。在0 - 40 μ g/ml的浓度范围内服从比尔定律。Pb（II）的检出限为0.036 μ g/ml。合成混合物和水样中铅（II）的回收率为98 ~ 99.8%，相对标准偏差（RSD）小于4%。该方法已成功地应用于标准物质、生物样品和环境水样中铅的测定。
Phenanthraquinone monophenyl thiosemicarbazone (PPT), an excellent color-forming chelating agent, combines to Pb(II) to form a slightly soluble complex in aqueous solution. To determine this metal ion, a tedious and time-consuming separation technique, such as liquid-liquid extraction, has to be performed. However, the Pb(II)-PPT complex could be determined conveniently by ultraviolet-visible (UV-Vis) spectrophotometry at 520 nm in a Tween 80 micellar medium that has polyoxyethylene groups. After conditions, such as the pH, the concentration of PPT and the stability, were adjusted to their optimum values, the sensitivities of the Pb(II) ions in the Tween 80 micellar medium and in chloroform were compared. It was shown that the sensitivity of Pb(II) in the Tween 80 micellar medium was higher than in chloroform. The interference from different cations and anions was studied. Beer's law was obeyed over a concentration range of 0 - 40 mu g ml(-1). The detection limit of Pb(II) was 0.036 mu g ml(-1). The recovery yields of the lead(II) in the synthetic mixtures and water samples ranged from 98 to 99.8%, and their relative standard deviations (RSD) were below 4%. The proposed method was successfully applied to the determination of lead in certified reference samples, biological samples and in environmental water samples.