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    锌(Ⅱ)-硫氰酸钾-藏红T反应体系分光光度法测定痕量锌

    Spectrophotometric Determination of Trace Amount of Zinc with the Reaction System of Zn(Ⅱ)-Potassium Thiocyanate-Safranine T

    • 摘要: 在pH3.6乙酸-乙酸钠缓冲溶液中,在曲拉通X-100存在下,锌(Ⅱ)与硫氰酸钾和藏红T(ST)反应生成稳定的离子缔合物[ST]4[Zn(SCN)6]。离子缔合物的最大吸收波长为482 nm,锌(Ⅱ)的质量浓度在0.006~0.70 mg·L-1范围内符合比耳定律,表观摩尔吸光率为5.41×104L·mol-1·cm-1。方法用于测定河水中锌,结果与双硫腙光度法一致。以河水样品为基体,用标准加入法做回收试验,测得平均回收率为99.4%,测定值的相对标准偏差(n=5)均小于3.5%。

       

      Abstract: In an acetate buffer medium of pH 3.6, and in the presence of Triton X-100, a stable ion association complex was formed between Zn(Ⅱ), in the form anionic complex of Zn(SCN)64-, and safranine T (ST+), having its empirical formula [ST]4[Zn(SCN)6]. The absorption maximum of the ion association complex was found at the wavelength of 482 nm. Lambert-Beer′s law was obeyed in the concentration range of 0.006-0.70 mg·L-1 for Zn(Ⅱ), with its apparent molar absorptivity of 5.41×104L·mol-1·cm-1. The proposed method was used in the analysis of 2 river water samples for their zinc contents, the results obtained were in consistency with the results found by the dithizone-photometric method. Tests for recovery was made by standard addition method using the river water samples as matrixes, value of average recovery was found to be 99.4% with RSD′s (n=5) less than 3.5%.

       

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