铬(Ⅵ)的方波伏安行为和测定

Square-Wave Voltampere Behavior of Cr(VI) Ion and Its Determination

在0.1 mol/L的氨水缓冲溶液(pH=10.0)中,铬(Ⅵ)离子于-1.45 V(vs S.C.E)出现一灵敏的方波伏安峰.峰电流Ip与Cr(Ⅵ)的质量浓度在0.1～2.0×103mg/L范围内呈现良好的线性关系,其相关系数为0.988 6,检出限为0.05 mg/LCr(Ⅵ),方法的标准偏差为2.8%.该法应用于实际样品电镀铬液及其废液中铬(Ⅵ)含量的测定,结果表明:与标准方法二苯碳酰二肼分光光度法比较,本法不需要加入特定的试剂而直接水样测定,简单快速.

Chromium (VI) ion showed a sensitive square-wave voltampere peak at -1.45 V (vs S.C.E) in the buffer solution of 0.1 mol/L ammonia liquor (pH=10.0). There appeared a good linear relationship between the peak current Ip and the mass concentration of Cr(Ⅵ) when it was within the range of 0.1 ~ 2.0 × 103 mg/L, the correlation coefficient of which was 0.988 6, the detection limit was 0.05 mg/L Cr (VI), and the standard deviation was 2.8%. The said method was used in determining the chrome (VI) contents in the sample of actual chrome plating solution and the waste liquor, the results of which showed that compared with spectrophotography with 1, 5-Diphenylcarbohydrazide, which is a standard method, this method does not need the addition of specific reagent but directly determines the water sample, which is simple and quick.