高碘酸盐光度法测定磷铁中锰

Determination of manganese in ferrophosphorus by periodate spectrophotometry

采用硝酸、氢氟酸、硫磷混酸处理磷铁样品,高碘酸盐光度法测定磷铁中的锰。实验确定了溶样酸体系,优化选择了525 nm作为测定波长,探讨了酸度和共存元素的影响。结果表明,基体中的Fe和P对测定影响不大,硫酸(1+1)、磷酸(1+1)加入量在20 mL以内时的干扰也可忽略不计。方法的检出限为0.003%。对磷铁标准样品和实际样品进行分析,结果同认定值或其他方法(碱熔酸化-分光光度法)测定值相一致,相对标准偏差为0.34%～2.2%。

With samples decomposed by nitric acid,hydrofluoric acid and mixed acid of sulfuric acid-phosphoric acid,Mn in ferrophosphorus was determined by periodate spectrophotometry.The acid system for sample dissolution was established, and the optimal measuring wavelength of 525 nm was selected.The influence of acidity and coexisting elements were discussed.The results showed that matrix elements of Fe and P had little influence on the determination.The interference could be neglected when the addition amount of sulfuric acid（1＋1） and phosphoric acid（1＋1） was within 20 mL.The detection limit for Mn was 0.003 %.The proposed method has been applied to the determination of ferrophosphorus certified reference materials and actual samples.The analytical results were consistent with the certified values and those obtained by alkali deliquescence-acidification spectrophotometry,and relative standard deviation（RSD） was between 0.34 % and 2.2 %.