动力学光度法测定低压锅炉循环水中的铬(VI)

Kinetics Spectrophotometry for the Determination of Cr(VI) in the Circulating Water of Low Pressure Boiler

本文依据Cr(VI)对H2 O2 氧化花青褪色的指示反应的催化作用 ,建立了测定微量Cr(VI)的停流流动注射 -催化动力学光度法。本法线性测定范围为 0～ 16 0ng·mL-1,方法检测限为 0 5ng·mL-1(3σ)。相对标准偏差为 0 7% (5 0ng·mL-1)。AI3 + 的干扰用F-掩蔽消除 ,而Fe3 + 和Cu2 + 的干扰则可用ED TA或硫脲消除。用本法测定了低压锅炉循环水和合成样品中的铬 (VI)含量 ,结果满意。

A stopped-flow injection catalytic procedure for the determination of trace chromium(VI)is described,based on the redox reaction between H 2O 2and gallocyanine catalysed by Cr(VI)in weak acid medium.The calibration graph is linear between 0～160ng·mL -1 The detection limit is 0.5 ng·mL -1 ,and the relative standard deviation is 0.7%(50ng·mL -1 ) The interfering effect of Al 3+ is eliminated by usiny F -as a masking agent,and those of Fe 3+ and Cu 2+ could be masked by both EDTA and thiourea.The Cr(VI)content in synthetic water sample and the circulation water in low pressure boiler had been determined.