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一、引言对于微量磷的测定,一般是用磷钼黄或磷钼蓝比色法。前者不适用于二氧化铀中磷的测定,因大量铀的黄色影响比色,必须分离,使操作比较复杂。后者只要通过波长为530—650毫微米滤光片比色,铀的存在是不干扰测定的。布利达德卡曾建议用硫脲为还原剂的磷钼蓝比色法。此法是基于在酸性溶液中,磷酸根与钼酸生成磷钼杂多酸H_7[P(Mo_2O_7)_6],此杂多酸被硫脲还原后成蓝色低价钼的化合物,借此比色测定磷。
I. Introduction For the determination of trace phosphorus, phosphorus molybdenum yellow or phosphorus molybdenum blue colorimetric method is generally used. The former does not apply to the determination of phosphorous dioxide in uranium dioxide, due to the large number of uranium yellow colorimetric, must be separated, making the operation more complicated. As long as the latter passes a colorimetric filter with a wavelength of 530-650 nm, the presence of uranium does not interfere with the assay. Blidaddeka has suggested using thiourea as a reductant phosphomolybdate blue colorimetric method. This method is based on the acid solution, phosphate and molybdate phosphomolybdic acid H_7 [P (Mo_2O_7) _6], the heteropoly acid thiourea reduced to blue low-molybdenum compounds, whereby the ratio Color determination of phosphorus.