用浓硝酸和浓高氯酸分解试液(镀液成份HEDP75、Cu10、Sn25、KNaC_4H_4O_625,Na_2HPO_430、NaNO_315克/升)使试液中的HEDP(羟基乙叉二膦酸)分解为正磷酸,然后以抗坏血酸还原磷铋钼络离子的钼蓝光度法进行总磷的测定,在不氧化的情况下同理测出无机磷的量,即可计算HEDP的量。一、试剂显色液:称取硝酸铋1克,溶于930ml稀硫酸(1+30)中,加入钼酸铵溶液(5%)100ml。磷酸氢二钠标准溶液:称取磷酸氢二钠0.231克,溶于水中,加硝酸5ml,以水稀释至1升。1ml磷酸氢二钠标准溶液相当于试样含量10gl~(-1)。此标准溶液用重量法进行标定。 HEDP (hydroxyethylidene diphosphonic acid) in the test solution is decomposed into orthophosphoric acid with concentrated nitric acid and concentrated perchloric acid decomposition test solution (HEDP75, Cu10, Sn25, KNaC_4H_4O_625, Na_2HPO_430, NaNO_315 g / L) Determination of total phosphorus by molybdenum blue photometry with ascorbic acid reduction of molybdenum bismuth molybdenum complex ion to calculate the amount of HEDP without the oxidation of the same amount of inorganic phosphorus measured. A reagent color reagent: Weigh 1 g of bismuth nitrate, dissolved in 930ml dilute sulfuric acid (1 +30), add ammonium molybdate solution (5%) 100ml. Disodium hydrogen phosphate standard solution: Weigh 0.231 grams of disodium hydrogen phosphate, dissolved in water, add nitric acid 5ml, diluted with water to 1 liter. 1ml sodium hydrogen phosphate standard solution equivalent to the sample content 10gl ~ (-1). This standard solution is gravimetrically calibrated.