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测定程序铋的测定用硝酸酸化试样溶液,并冲淡至每100毫升含铋80毫克。加3—5滴指示溶液。如果冲淡后的溶液酸度合宜,会有蓝的色彩;如果颜色是青紫色的,酸度就是过大,必须用氨水溶液仔细调整至pH2—3。正确的pH可由蓝色色彩的出现而指出。用标准EDTA溶液滴定至溶液由蓝变黄,在刚到达终点之前出现临时性的紫色(1)。滴定可以用淡的EDTA溶液(0.002克分子以下)进行。本法非常准确,能用於EDTA溶液以金属铋或氧化铋
Assay Procedure Bismuth Assay The sample solution was acidified with nitric acid and diluted to 80 mg bismuth per 100 ml. Add 3-5 drops of indicator solution. If the acidity of the diluted solution is appropriate, there will be a blue color; if the color is blue, the acidity is too large, you must carefully adjust the pH to 2-3 with ammonia solution. The correct pH can be indicated by the appearance of a blue color. Titrate with a standard EDTA solution until the solution turns yellow to blue and a temporary purple color (1) appears just before reaching the end point. Titration can be performed with a weak EDTA solution (0.002 moles or less). This method is very accurate and can be used in EDTA solution to bismuth or bismuth oxide