双波长叠加分光光度法测定水中微量氰化物

在弱酸性介质中和氯胺T存在条件下,CN-可与异烟酸-硫代巴比妥酸形成一蓝色染料,该染料具有两个吸收峰,分别位于642 nm和525 nm处,且其在两波长处的吸光度之和△A(△A=Aλ1+Aλ2)与氰化物含量在一定的范围内呈良好的线性关系,据此建立了测定水样中微量氰化物的异烟酸-硫代巴比妥酸双波长叠加分光光度法.该法氰化...

DETERMINATION OF TRACE CYANIDE IN WATER BY SPECTROPHOTOMETRY WITH DUAL-WAVELENGTH SUPERPOSITION

A new dual - wavelength superposition - spectrophotometry for determination of cyanide was proposed. In weakly acidic solution and in the presence of chloramine T, cyanide reacted with isonieotinic acid - thibarbiturie acid to form dye with 2 ab- sorption peaks at wavelengths of 642 nm and 525 nm in its absorption spectrum. By applying the measurement mode of ＂absorbance ad- dition at 2 wavelengths＇and taking the sum of values of absorbances at 525 nm and 642 nm（△A=Aλ1＋Aλ2）） , linear relationship be- tween the values of sum of absorbances and mass concentration of cyanide was obtained in the range of 0 -4.0 ~g/（ 10.0 mL）. The method was applied to determine cyanide in water and the results accorded with those measured by standard method. The relative stand- ard deviation of standard solution determination resuhs was less than 4% （ n = 5 ）.