甲基异丁基甲酮萃取磷钼杂多酸-钼火焰原子吸收光谱法间接测定钢中磷

在0.01～1.0mol/L的盐酸介质中,磷酸根与钼酸铵形成磷钼杂多酸,用甲基异丁基甲酮萃取,以火焰原子吸收光谱法测定磷钼杂多酸中的钼,据此建立了一种间接测定钢中微量磷的新方法。选择溶解体系为王水+HF+H2O2;萃取条件为:5.0mL的甲基异丁基酮,振荡时间为3min,2.0mL20g/L钼酸铵溶液。当磷的含量在0.04～1.00mg/L范围内时,吸光度与浓度呈良好的线性关系;方法的检出限为0.015mg/L。对钢标准样品中微量磷的测定,结果与认定值相符,RSD为0.7%～4.8%。

Indirect determination of trace phosphorus in steel by flame atomic absorption spectrometric determination of molybdenum after extraction of heterphosphomolybdic acid with methyl isobutyl ketone

In the medium of 0.01-1.0 mol/L HCl,phosphate radical reacts with ammonium molybdate to form a heterphosphomolybdic acid which is extracted with methyl isobutyl ketone and then determined by flame atomic absorption spectrometry(FAAS).Based on this,a method for indirect determination of phosphorus in steel is established.The sample is digested with agua regia,HF and H_2O_2(8 mL 0.5 mL 2 mL).The extraction condisions are as follows:the volume of methyl isobutyl ketone is 5.0 mL,the volume of ammonium molybdate is 2.0 mL,oscillating time is 3 min.A good linear relationship was obtained between the absorbance and the concentration of phosphorus in the range of 0.04-1.00 mg/L and the detection limit is 0.015 mg/L.The method has been applied to the determination of phosphorus in certified reference materials with RSD of 0.7%-4.8% and the determination results were conform with the certified values.