Benamor M, Belhamel K, Draa M T
Laboratory of Analytical Chemistry, Institute of Chemical Engineering, University of Bejaia, Algeria.
J Pharm Biomed Anal. 2000 Nov;23(6):1033-8. doi: 10.1016/s0731-7085(00)00366-6.
A simple, rapid, and sensitive spectrophotometric method for the determination of zinc(II) is performed, based on colour reaction between the metal ion and xylenol orange in the presence of surfactant cationic cetylpyridinium chloride. The important analytical parameters and their effects on the reported system are investigated. Zinc(II) reacts with the reagent and surfactant in the ratio 1:2:4 (metal:ligand:surfactant) in the pH range 5.0-6.0 to form a ternary complex with an absorption maximum at 580 nm. The reaction was extremely rapid, at room temperature, and the absorbance value remains unchanged for at least 168 h. The apparent stability constant of the complex was found to be K = 1.05 x 10(10), and the method adheres to Beer's law for 1-20 microg zinc(II) per 25 ml with apparent molar absorptivity of 1.1 x 10(4) l mol cm(-1). The effect of foreign ions was tested by taking a constant concentration of metal ion and determining its concentration in the presence of large number of foreign ions. The method was applied for determination of zinc(II) in dermal ointments where excellent agreement between reported and obtained results were achieved. The relative standard deviation was better than 2%.
基于金属离子与二甲酚橙在表面活性剂阳离子十六烷基吡啶氯化物存在下的显色反应，建立了一种简单、快速、灵敏的分光光度法测定锌（II）。研究了重要的分析参数及其对所报道体系的影响。在pH值5.0 - 6.0范围内，锌（II）与试剂和表面活性剂按1:2:4（金属:配体:表面活性剂）的比例反应，形成一种在580 nm处有最大吸收的三元配合物。该反应在室温下极其迅速，吸光度值至少168小时保持不变。配合物的表观稳定常数为K = 1.05×10(10)，该方法在每25 ml含1 - 20 μg锌（II）时符合比尔定律，表观摩尔吸光系数为1.1×10(4) l·mol·cm(-1)。通过固定金属离子浓度并在大量外来离子存在下测定其浓度来测试外来离子的影响。该方法用于测定皮肤软膏中的锌（II），所报道结果与所得结果之间取得了极好的一致性。相对标准偏差优于2%。
