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    二溴四苯基卟啉分光光度法测定水样中铅

    Spectrophotometric Determination of Lead in Water Samples with Dibromo-tetraphenylporphyrin as Chromogenic Reagent

    • 摘要: 研究了显色剂二溴四苯基卟啉与铅(Ⅱ)的显色反应。在Tween-80微乳液及pH 12的磷酸氢二钠-氢氧化钠缓冲溶液中,铅(Ⅱ)与显色剂形成1∶1的稳定配合物。 其最大吸收位于472 nm波长处,表观摩尔吸光率为2.2×104 L·mol-1·cm-1。铅(Ⅱ)的质量浓度在180 μg·L-1以内符合比耳定律。方法用于环境水样中铅(Ⅱ)的测定,回收率在99.9%~102.0%之间。

       

      Abstract: Dibromo-tetraphenyl-porphyrin (DBTPP) was used as a new chromogenic reagent for determination of lead(Ⅱ), and conditions for the colour reaction were studied. In a Na2HPO4-NaOH buffer solution of pH 12, and in the presence of Tween-80, a stable coordination complex with the molar ratio [Pb(Ⅱ)∶(DBTPP)] of 1 to 1 was formed, with its absorption max. at the wavelength of 472 nm. Value of apparent molar absorptivity was found to be 2.2×104L·mol-1·cm-1. Beer′s law was held in the range within 180 μg·L-1. The proposed method was applied to the determination of lead in environmental water samples, giving values of recovery in the range of 99.9%-102.0%.

       

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