铜含量42%、铝含量58%的铝铜中间合金使用拟定方法分析,终点明显,步骤简单,相对偏差约0.2%。称取0.5000克试样,经盐酸(1+1)-过氧化氢分解后煮沸破坏过氧化氢,以水定容至250毫升。①分取10毫升试液,加入氟化铵掩蔽铝,以六次甲基四胺为缓冲液调至 pH5.4,准确加入20毫升0.05MEDTA 标准溶液,以二甲酚橙为指示剂,用0.025M铅标准溶液滴定至橙红色,所消耗的体积为 V_1;②同理,移取20毫升0.05MEDTA 标准溶液,调 pH 后 Copper-aluminum content of 42%, 58% of the aluminum-copper master alloy analysis using the proposed method, the end point is obvious, the steps are simple, the relative deviation of about 0.2%. Weigh 0.5000 grams of the sample, after hydrochloric acid (1 +1) - hydrogen peroxide decomposition of hydrogen peroxide destruction of boiling water to 250 ml. ① sub-10 ml of test solution, add ammonium fluoride masking aluminum, hexamethylenetetramine as buffer to pH5.4, accurately add 20 ml of 0.05MEDTA standard solution, with xylenol orange as indicator, with 0.025M lead standard titration to orange-red solution, the volume consumed V_1; ② Similarly, Pipette 20 ml 0.05MEDTA standard solution, after adjusting pH