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1—(8—羟基喹琳—7—偶氮)—对硝基苯(HQANB)是我们合成的一种金属离子高灵敏显色剂,已用于金属离子镍的测定。本文研究了该试剂与CU(Ⅱ)发生螯合反应的条件及螯合物的光度分析性能,并探讨了用消色法测定微量铜的可能性。采用此法,可不经分离,直接用于铝合金中微量铜的测定,其结果令人满意。 1 试验部分1.1 主要试剂与仪器铜标准溶液:称取纯铜0.1000g于150ml锥形瓶中,加HNO_3(1+3)15ml溶解,煮沸除去氮的氧化物,冷却后移入1000ml量瓶中,以水稀至刻度,摇匀。此溶液含铜100μg·L~(-1),用时稀释成含铜5.0μg·L~(-1)的工作液。 HQANB溶液:4.0×10~(-3) mol·L~(-1),称此纯品0.294g于洁净250ml烧杯中,加乙醇(95%)100ml和氢氧化钠溶液(20%)5d,溶解后移入250ml量瓶中,用乙醇(95%)稀至刻度,摇匀。
1- (8-hydroxyquinoline-7-azo) -p-nitrobenzene (HQANB) is a highly sensitive metal ion sensitizer that we have synthesized for the determination of metal ion nickel. In this paper, the conditions for the chelation reaction of this reagent with CU (Ⅱ) and the photometric analysis of the chelates were investigated. The possibility of determining trace amounts of copper by decoloration was also discussed. Using this method, without separation, direct determination of trace amounts of copper in aluminum alloy, the results are satisfactory. 1 Experimental 1.1 The main reagents and equipment Copper standard solution: Weigh copper 0.1000g in 150ml conical flask, add HNO3 (1 +3) 15ml dissolved, boiled to remove nitrogen oxides, cooled and transferred to a 1000ml volumetric flask, Dilute to the mark with water, shake well. The solution containing copper 100μg · L ~ (-1), diluted with time into a working solution containing copper 5.0μg · L -1. HQANB solution: 4.0 × 10 -3 mol·L -1, said pure product 0.294g In a clean 250ml beaker, add ethanol (95%) 100ml and sodium hydroxide solution (20%) 5d, Dissolved into 250ml volumetric flask, diluted with ethanol (95%) to the mark, shake.