クロラニル酸とスズ(IV)との錯体による硫酸イオンの比色定量法 : 二酸化鉛法による大気中の硫黄酸化物の定量への応用

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Tin (IV)-chloranilate complex was used in the determination of sulfate. The principle of this method is based on the colorimetry of the purple solution of tin (IV)-chloranilate complex produced by barium chloranilate and tin (IV) ion in dil, hydrochloric acid. The procedure was as follows : to 10 ml of a sample solution were added, 10 ml of 99.5% ethanol and 0.1 g of barium chloranilate in that order, shaken for 10 min, and filtered. A 10 ml aliquot of the filtrate was mixed with 2.0 ml of tin (IV) chloride solution in dil. hydrochloric acid. The absorbance of developed color of tin (IV)-chloranilate complex was measured at 540 mμ after about 10 min. The standard deviation was 1.4% on an average absorbance 0.344 of samples containing 120 ppm of SO^<2->_4. It is necessary to use cation exchanger resin in order to eliminate interfering ions. The spectrophotometric procedure can be applied to the determination of sulfate in lead candle dioxide which has been exposed to atmospheric sulfur pollution. As absorbance of tin (IV)-chloranilate complex is constant over a wide range of pH values, it is unnecessary to use a buffer solution. Therefore, the method described above will be more convenient than the gravimetric method commonly used as PbO_2 method.
1970-10-31