磷钒钼黄光度法快速测定铜合金中磷的方法应用及理论探讨

Fast Determination of Phosphor in Copper Alloy By Phosphor-vanadium-molybdenum-yellow Photometry and its Theoretical Discussions

试样经盐硝混合酸溶解，以过氧化氢将亚磷酸氧化成正磷酸，在酸性介质中，加入钒酸铵和钼酸铵与磷酸形成黄色的磷钒钼三元杂多酸，从而进行磷的测定。磷钒钼三元缔合物形成的适宜酸度为C（H^＋）：0．2～1．6mol／L。酸度过高则显色过慢，甚至抑制显色反应的完成，酸度太低则硅干扰，所以，含硅铜合金试样酸度不应低于C（H^＋）=0.5mol／L。

After samples are dissolved with combined solution of hydrochloric acid and nitric acid, hydrogen peroxide is used to oxidize phosphorous acid into orthophosphoric acid. In acidic medium, ammonium vanadate and ammonium molybdate are added, which, with phosphorous acid ,form yellow ternary acid of phosphor, vanadium and molybdenum, by which the content of phosphor can be determined. Fitting acidity formed by the ternary associated substance is C（ H^＋ ） =0. 2 - 1.6mol/L. If acidity is too high,coloration will be too slow,moreover it even will restrain complete coloration while if acidity is too low, silicon disturbance will happen. So the acidity of samples containing silicon and copper shall not be lower than C（ H^＋ ） =0. 5mol/L