流动注射化学发光法快速测定化学需氧量

Chemiluminescence determination of aquatic COD with flow injection analysis

基于酸性K2 Cr2 O7在消解水体中的有机污染物时被还原为Cr(Ⅲ ) ,而Cr(Ⅲ )可以催化Luminol H2 O2 体系产生强的化学发光 ,建立了一种测定COD的流动注射化学发光法。本方法不需要催化剂 ,不需要长的消解时间 ,可以采用较低的酸度 ,适合于在线连续检测水体COD。本方法检测COD的线性范围为 2 0～1 0 0 0 0mg L ,检出限为 1 0mg L ,对 1 0mg LCOD的 1 1次平行测定的RSD小于5 %。方法已用于地表水样COD的测定。

A novel chemiluminescence (CL) system combined with flow injection for determination of chemical oxygen demand (COD) of aquatic system was described. The acidic K_2Cr_2O_7 was reduced into Cr(Ⅲ)by reducible substances in water, and the generated Cr(Ⅲ) catalyzed the luminol-H_2O_2 system to produce the strong CL emission. The reduction reaction did not need other catalyzer and the analysis was completed on-line. The linear range of determination fo COD was 20～10000 mg/L with the detection limit of 10 mg/L. The whole analysis could be completed in 1 min. The system was applied to determine the COD of the water sample with satisfactory results.