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试剂钴亚硝酸钠溶液:称取硝酸钴[Co(NO_3)_2]25克,加水75毫升溶解;再称取亚硝酸钠55克,加水75毫升溶解,然后混合。加入5%乙酸20毫升,放置一夜,使 NO 气体逸去,过滤,备用。溶液应为橙色,如变红色,表示已分解,应重配。乙酸-乙酸钠缓冲溶液:pH=5.5,每升溶液中含结晶乙酸钠200克,冰乙酸10毫升。分析方法取含钾盐约0.5%的试液25毫升,加热至50～60℃,加入5%乙酸3毫升,钴亚硝酸钠溶液15～20毫升,搅拌1分钟,并保温陈化1小时以上(不要超过50～60℃)。冷却,以中速滤纸过滤,以1%乙酸洗
Reagents cobalt sodium nitrite solution: Weigh cobalt nitrate [Co (NO_3) _2] 25 g, add water 75 ml dissolved; then weighed 55 grams of sodium nitrite, dissolved in 75 ml of water and then mixed. 20ml of 5% acetic acid was added and left to stand overnight so that NO gas escaped, filtered and reserved. Solution should be orange, such as turning red, that has been decomposed, should be re-allocated. Acetic acid-sodium acetate buffer solution: pH = 5.5, containing 200 g of crystalline sodium acetate per liter of solution and 10 ml of glacial acetic acid. Analysis method Take about 0.5% of the potassium salt test solution 25 ml, heated to 50 ~ 60 ° C, adding 5% acetic acid 3 ml, 15-20 ml cobalt sodium nitrite solution, stirring for 1 minute and heat aging for more than 1 hour (Do not exceed 50 ~ 60 ℃). Cool, filter at medium speed filter paper, wash with 1% acetic acid