自配消解液分光光度法测定污水中的COD

以自配消解液代替ThermoFisher公司AQ4001COD测定系统的专用消解液，比较了自配消解液分光光度法与国家标准重铬酸钾法(GB 11914-1989)测定化学需氧量(COD)的差异。对比试验表明，自配消解液分光光度法测定COD的结果精确度和准确度高，与国家标准方法无显著性差异。自配消解液分光光度法测定水样COD值的相对标准偏差;低量程(30～150 mg/L)为1.38%～2.53%，中量程(0～1 500 mg/L)为0.47%～3.63%，高量程（2 000～15 000 mg/L）为0.17%～3.53%，在国家标准方法测试水样COD值的允许误差范围内。除制革废水外，自配消解液可以代替AQ4001COD测定系统的专用消解液，适用不同量程范围内污水COD的测定。自配消解液分光光度法具有试剂使用量少、速度快、经济、二次污染小等优点，值得在环境科学领域及废水水质监测中推广应用。

Determination of COD by spectrophotometry with self-prepared digestion solution

Determination of COD by spectrophotometry is performed by replacing the high-cost special digestion reagent of ThermoFisher's AQ4001COD system with the self-prepared digestion solution in the present study. The results showed that COD determination by spectrophotometry with self-prepared digestion solution exhibits a higher precision and accuracy. Furthermore, no significant differences for COD determination value are found between China national standard method (GB 11914-1989) and the above-mentioned spectrophotometry with self-prepared digestion solution . The standard deviation of COD determination values by spectrophotometry with self-prepared digestion solution varies from 1. 38% to 2. 53% for water sample with a lower COD concentration from 30 to 150 mg/L ,from 0. 47% to 3. 63% for water sample with a middle COD concentration ranged from 0 to 1 500 mg/L, and from 0. 17% to 3. 53% for water sample with a higher COD concentration of more than 3 000 mg/L. It is concluded that COD determination by spectrophotometry with self-prepared digestion solution is suitable to determine COD values for all kinds of water samples instead of tannery wastewater. The method of spectrophotometry has the advantages of small quantity of reagent, speed measurement, economization and low pollution,and should be applied popularly in the field of environmental science and wastewater analysis.