ピロガロールレッド-モリブデン(VI)錯体を用いる硫酸キニーネの定量

キサンテン系誘導体の有機試薬としての利用研究(第17報)

抄録

A rapid and simple method for the spectrophotometric determination of micro amounts of quinine sulfate with pyrogallol red(PR) and molybdenum(VI) in the presence of polyoxyethylenesorbitanmonolaurate (LT-221) at pH 4.5 was established. The calibration curve for the spectrophotometric determination was linear in the range of 01.12 mg quinine sulfate/10 ml. The sensitivity was 0.082μg quinine sulfate/ml for absorbance of 0.001. The recommended analytical procedure is as follows. A sample solution containing less than 1.12 mg of quinine sulfate is taken in a 10 ml measuring flask, and 1.0 ml of 5.0×10^-4 M molybdenum(VI), 0.5 ml of 2.0 % LT-221 solution and 0.5 ml of 1.0×10^-3 M PR solution are added, and then the resulting solution is adjusted to pH 4.5 with Walpole acetate buffer solution. The content is diluted to the mark with water, kept at (2025)°C for 50 min, and the absorbance of the PR-molyb-denum(VI)-quinine sulfate solution(A solution) is measured at 610 nm against PR-molybdenum(VI) solution (B solution). The effect of foreign substances on the absorbance were examined. Aluminum(III), iron(III) and chromium(VI) interfered, but could be masked by the addition of sodium fluoride or EDTA solution.