停流─—反相流动注射分析法测定环境水样的化学需氧量

DETERMINATION OF CHEMICAL OXYGEN DEMAND IN AQUEOUS ENVIRENMENTAL SUMPLES BY STOP-REVERSE FLOW^INJECTION METHOD

以铈（IV）作氧化剂，停流——反相流动注射分析法快速测定环境水样的化学需氧量。方法测定范围2．5～160mg／L，采样频率12h－1。检测下限和标准偏差分别为2．5mg／L和0．9％，cl－至2000mg／L无明显干扰，与经典的重铬酸钾法相对照，结果相关性良好。试剂费用节约95％以上，分析周期缩短至1／24且污染小。

A method using cerium (IV) sulphate as oxidizing agent is described for the determination of chemincal oxygen demand (COD) in aqueous environmental samples by stop-reverse flow-injection with the range of 7. 5- 160mg/L. COD values for sample correlate well with those obtained by standard manual method, except for higher frequency.Less polution and more economical costs. The detection limit and relative standard deviation of the method are 2. 5 mg/L and 0. 9% respectively. Chroride ion up to the levels of 2000 mg/L does not interfere 1 and a sumple throughout of 12h-1 can be achieved.