磷钼蓝分光光度法测定工业硅中磷

采用氢氟酸-硝酸溶解样品,高氯酸冒烟驱除硅、氟,加入抗坏血酸、显色溶液后直接显色测定,建立了磷钼蓝分光光度法测定工业硅中0.001%～0.27%磷含量的分析方法。结果表明,溶液中磷质量浓度在0.05～1.40 μg/mL范围内符合比尔定律;方法中磷的检出限为0.000 46 μg/mL;表观摩尔吸光系数ε₈₂₅=2.75×10⁴ L·mol^-1·cm^-1;样品中其他共存离子不干扰测定。不同实验室应用实验方法测定3个工业硅行业标准样品中磷的结果均与认定值吻合;按照实验方法测定2个工业硅行业标准样品中磷的结果与国标方法GB/T 14819.4－2012和GB/T 14819.5－2012的测定值均基本一致。将实验方法用于工业硅行业标准样品和工业硅实际样品中0.001%～0.27%磷的测定,实验所得结果的相对标准偏差(RSD,n=22)为1.4%～4.5%。

Determination of phosphate in industrial silicon by phosphomolybdenum blue spectrophotometry

The industrial silicon sample was dissolved with hydrofluoric acid and nitric acid. After removing silicon and fluorine by perchloric acid fuming, ascorbic acid and the color developing solution were added successively for coloring followed by direct determination. Thus, an analysis method of phosphorus content (0.001%-0.27%) in industrial silicon by phosphomolybdenum blue spectrophotometry was established. The results showed that Beer’s law was obeyed for mass concentration of phosphorus in range of 0.05-1.40 μg/ mL. The detection limit of method was 0.000 46 μg/mL. The apparent molar absorptivity was ε₈₂₅=2.75×10⁴ L·mol^－1·cm^－1. Other coexisting ions in sample had no interference. The content of phosphorus in three industrial silicon industry reference materials was determined according to the experimental method in different laboratories, and the results were consistent with the certified values. The content of phosphorus in two industrial silicon industry reference materials was determined according to the experimental method, and the results were both consistent with those obtained by national standard methods GB/T 14819.4-2012 and GB/T 14819.5-2012. The proposed method was applied to the determination of phosphorus (0.001%-0.27%) in industry reference materials and actual samples of industrial silicon. The relative standard deviations (RSD, n=22) were between 1.4% and 4.5%.