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利用NO_2~-在0.5-1N HCl介质中氧化二苯硫腙的褪色反应,用萃取平衡控制反应时间和水相中二苯硫腙的浓度,建立了非催化动力学分析法测定NO_2~-的新方法.反应速度的检测,是在620nm下测定反应前后CCl_4相中二苯硫腙的吸光度变化.方法灵敏度为8×10~(-3)g·ml~(-1)NO_2~-,线性范围是0.8～5μg NO_2~-/10ml.对干扰严重的金属离子Cu~(2+)、Cu~+、Ag~+、Hg~(2+)、Au~(3+)等可在pH 3～7条件下,用二苯硫腙的CCl_4溶液萃取除去.用该法测定废水中的NO_2~-,与用生成偶氮染料比色法测定结果一致.方法的精密度:对三个试样各6次测定的变动系数分别为0.6%,0.9%,和1.5%.
The decolorization reaction of NO2 ~ - oxidized dithizone in 0.5-1N HCl medium was carried out. The equilibrium reaction time and the concentration of dithizone in the aqueous phase were controlled by extraction equilibrium. The kinetic analysis of NO2 ~ - The new method was used to determine the reaction rate, which was the change of absorbance of dithizone in CCl 4 phase before and after reaction at 620 nm.The sensitivity was 8 × 10 -3 g · ml -1 NO 2 - The range is 0.8 ~ 5μg NO_2 ~ - / 10ml. For the serious interference of metal ions Cu ~ (2 +), Cu ~ +, Ag ~ +, Hg ~ (2 +), Au ~ (3 + ~ 7 conditions, with diphenylhydrazone CCl_4 solution was removed by this method for the determination of NO_2 ~ - wastewater, with the formation of azo dye colorimetric determination of the results of the method of precision: the three samples The coefficient of variation for each of the six determinations was 0.6%, 0.9%, and 1.5%, respectively.