ICP-AES测定铁系催化剂中硫酸盐的方法研究

Study on the Method for Determination of Sulfate in Fe-catalyst by Inductively Coupled Plasma Atomic Emission Spectrometry

研究探讨了ICP AES测定铁系催化剂中硫酸盐所存在的干扰问题 ,建立了ICP AES测定其中硫酸盐的方法。实验发现 ,铁的存在对SO2 -4的测定不仅存在背景干扰 ,而且严重抑制硫的谱线强度 ,其抑制程度和背景干扰程度都随铁含量的增加而增强 ;盐酸酸度在 2 %以下 ,不影响SO2 -4的测定 ,但随着盐酸酸度的增加 ,由于溶液粘度的变化所引起的物理干扰而抑制硫的谱线强度。因此 ,应采用基体匹配法测定铁系催化剂中的硫酸盐。所建的方法简单、快速 ,结果重现性好 ,SO2 -4的检出限为 0 16mg·L-1,六次测定相对标准偏差小于 3% ,样品加标回收率为 97 0 %～ 10 0 4 %。

A direct method was reported for the determination of sulfate in iron-catalyst by inductively coupled plasma atomic emission spectrometry (ICP-AES). The samples were dissolved with hydrochloric acid. The interference factors of hydrochloric acid and iron were studied. The results showed that the effect of iron on the test of sulfate was not only to cause background interference but also to depress the intensity of sulfur seriously as well, and the effect increased with the increment of iron amount. Due to the physical interference, a high concentration of HCl also depresesed the intensity of sulfur. Matrix effect from iron and HCl were corrected by matrix matching method. The recommended method is simple and rapid, and show satisfying precision and accuracy. The recoveries were more than 97%, and the relative standard deviations of six samples were less than 3%.