磷钼酸喹啉重量法对高含量磷样品的测量准确、精度高,但不适用于低价磷化合物的含量测定。为了解决该缺陷,提出了一种新方法：先氧化次亚磷酸再测定,并探究合适的氧化剂及氧化、沉淀条件。实验表明,硝酸铈铵作为氧化剂运用到磷钼酸喹啉形成之前,可以把低价磷定量转化为高价磷从而使低价磷能够与沉淀剂响应而被测定,为确保低价磷的转化完全,过量加入的硝酸铈铵须加热至沸腾20 min以上除尽,否则会影响后续操作。该法对同时含有多种形态磷的复杂样品可分别测出样品中含有的正磷酸含量、总磷含量、次亚磷酸含量,具有很好的实际应用价值。

The quinoline phosphomolybdate gravimetric method is accurate and precise in measuring high-content phosphorus samples,but it is not suitable for the determination of low-priced phosphorus compounds.In order to solve this defect,a new method was proposed：the hypophosphite was oxidized first and then determined,the appropriate oxidant and oxidation and precipitation conditions were explored.Experiments showed that cerium ammonium nitrate could be used as an oxidant before the formation of quinoline phosphomolybdate,which could quantitatively convert low-valent phosphorus into high-valent pho-sphorus so that low-valent phosphorus could be measured in response to the precipitation agent,in order to ensure complete conversion of low-valent phosphorus.The excessively added cerium ammonium nitrate should be heated to boiling for more than 20 minutes to remove it,otherwise it would affect the subsequent operation.This method could detect the orthophosphoric acid content,total phosphorus content,and hypophosphorous acid content of complex samples containing multiple forms of phosphorus at the same time,and had good practical application value.