二苯硫腙还原法测定痕量 NO_2^-

Determination of trace NO_1^(?) by reduction Method of Dithizone

NO_2^-在2MHCl 介质中能氧化二苯硫腙,使四氯化碳相中绿色减退。通过测定620nm 下反应前后四氯化碳中吸光度的改变,建立了测定痕量 NO_2^-的新方法。方法的灵敏度ε=3. 45×10~4升·摩尔^(-1) ·厘米^(-1) ,最低检出限为5. 0×10^(-8) gNO_2^-·ml^(-1) ,线性范围为0. 50-7. 5μg·NO_2^-·10ml^(-1) 。对干扰的金属离子 Cu^+、Cu^(+2) 、Hg^(2+)、Ag^+、Au^(3+)等,可在 pH3-7条件下,用二苯硫腙的四氯化碳溶液萃取除去。该法用于测定废水中 NO_2^-,结果是满意的。

Based on the decoloration of NO_2^-oxidize dithizone in 2M HCl medium,a new method for the determination of trace NO_2^-is developed by means of monitoring the absorbance change in C Cl_4 phase at 620nm.The apparent molar absorptivity of the method is 3. 45×10~4L·mol^(-1) ·cm^(-1) ,the detection limit is 5. 0×10^(-8) g NO_2^-·ml^(-1) ,and the linear range is 0. 5 to 7. 5μg NO_2^-per 10ml.The interfering metal ions can be separated by extraction with dithizone-C Cl_4 solution at PH 3-7. The method has been applied to the determination of NO_2^-in polluted water with satisfactory result.