金的测定—碘量法以浓盐酸破坏氰化物(柠檬酸铵镀金液中尚含有少量氰化物),以过硫酸铵氧化破坏柠檬酸铵,过量的过硫酸铵煮沸除去,然后以碘量法测定。一试剂硫代硫酸钠标准溶液:0.1N,称取硫代硫酸钠Na_2S_2O_3·5H_2O_(25)克,溶于1升新煮沸并冷却的水中,加入Na_2CO_3约0.2克,保存于棕色试剂瓶中,置于暗处,一天以后以0.1N重铬酸钾标准溶液标定,以 Determination of gold - Iodometric method to destroy the cyanide with concentrated hydrochloric acid (ammonium citrate gold plating solution also contains a small amount of cyanide), ammonium persulfate oxidative destruction of ammonium citrate, excess ammonium borate to remove boiled, and then iodometric method Determination. A reagent sodium thiosulfate standard solution: 0.1N, weighed sodium thiosulfate Na_2S_2O_3 · 5H_2O_ (25) grams, dissolved in 1 liter of freshly boiled and cooled water, add about 0.2 grams of Na_2CO_3, stored in a brown reagent bottle, Placed in the dark, one day later with 0.1N potassium dichromate standard solution to