摘要
本文用硝酸和高氯酸将HEDP分解为正磷酸根,然后在酸性溶液中加入钒酸铵和钼酸铵,生成黄色磷钒钼酸络合物,以水为空白对照液,用3cm的出色皿,在721分光光度计上,于470nm处进行比色测定。这样测得的磷量实际是总磷量,它包括了由HEDP分解出来的磷酸根和溶液中可能存在的磷酸氢二钠中的磷酸根。因此,HEDP的量应该由总磷量减去溶液原来存在的磷酸根的量,再计算而得。溶液中原来存在的磷酸根的量,可以将试液不经硝酸和高氯酸氧化,直接加钒酸铵和钼酸铵,用比色法测得。与其它方法相比,本法具有准确度高、速度快、操作方便等优点。
HEDP can be decomposed to phosphate by nitric acid and perchloric acid, then ammonium vanadate and ammonium molybdate are added into this acidic solution and a yellow complex compound of phospho vanadic molybdate is produced. With water as blank reference solution, the colorimetric determination is carried out with 3cm comparison tube, on 721 spectrophotometer at 470nm. The amount thus obtained is the total one. also including the phosphate of NaH_2PO_4, which may exist in the solution. Therefore, the HEDP amount should be calculated from the difference of the total amount and the amount of phosphate originally existing in the solution, which can be determined with colorimetric method, by adding ammonium vanadate and ammonium molybdate directly without oxidation with nitric acid and perchloric acid. It is superior to all other methods for its high accuracy, rapidity and convenience.
出处
《电镀与环保》
CAS
CSCD
1989年第1期30-31,共2页
Electroplating & Pollution Control
