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离子选择电极测微量氯,是以溴化钾还原氯为氯离子,用氯电极为指示电极,用电位法测定氯离子的含量,但过量溴必须除去。若用碘化钾还原也须除去过量碘。操作麻烦,不易控制。我们用碘化钾还原氯为氯离子,用碘离子选择电极测定过量碘离子来确定水中游离氯的含量。方法简便,快速,干扰少,能测0.1～1ppm氯。测定结果满意。实验部分 1.仪器与试剂:pHS-2型酸度计,303 型碘离子选择电极,217型甘汞电极;碘化钾标准溶液,pH_4柠檬酸缓冲液。 2.操作步骤: (1)工作曲线:取六只50毫升容量瓶,分别加入1.0MKNO_3,10~(-3)MKI及柠檬酸缓冲液,再分
Ion-selective electrode to measure trace chlorine, potassium bromide is used to reduce chloride to chloride ion, with chlorine electrode as the indicator electrode. Chloride ion content is determined by potentiometric method, but excess bromine must be removed. If potassium iodide reduction also need to remove excess iodine. Operation trouble, not easy to control. We use chlorine iodide to reduce chloride to chloride ion, and use iodide ion selective electrode to determine excess iodide to determine the content of free chlorine in water. Method is simple, fast, less interference, can measure 0.1 ~ 1ppm chlorine. Satisfactory results. Experimental part 1. Instruments and reagents: pHS-2 type acid meter, 303 iodine ion selective electrode, 217 calomel electrode; potassium iodide standard solution, pH_4 citrate buffer. 2 steps: (1) working curve: Take six 50 ml volumetric flask, respectively, by adding 1.0MKNO_3,10 ~ (-3) MKI and citrate buffer, subdivision