催化褪色光度法测定化学试剂中氯化物

Determination of chloride by catalytic spectrophotometry in chemical regent

建立了一种测定氯化钠含量的新的催化褪色光度法。在稀硫酸介质中,利用氯化钠对溴酸钾氧化甲基橙褪色反应的催化作用,使甲基橙在最大吸收波长510nm处的吸光度明显降低,且此吸光度的降低ΔA与氯化钠的浓度呈定量关系。氯化钠的含量在0～20μg·mL^(-1)范围内与ΔA呈线性关系,方法的检测限为1.46×10^(-7)μg·mL^(-1),用于化学试剂中氯化物杂质含量的测定,加标回收率为94.7%～95.9%。结果满意。

A new catalytic spectrophotometry for the determination of sodicm chloride in chemical regent was established. The absorption of methyl orange at the wavelength of 510nm decreased due to the decoloration of methyl orange in a oxidation reaction with potassium bromate being catalyzed by sodium chloride in a medium of dilute sulfuric acid solution. There wss a quantity relation between decrease of absorption with the amount of sodium chloride, The decrease of absorption was linearly proportional to sodium chloride concentration in the range of 0- 20μg·mL^-1. Detection limit of the method was 1.46× 10^-1μg·mL^-1 and the recovery was 94.7 %-95.9%.