分光光度法测定催化剂中镧含量

Spectrophotometric Method for the Determination of Lanthanum in Catalysts

提出用分光光度法测定催化裂化干气制乙苯催化剂中镧含量的方法。用偶氮胂（Ⅲ）作显色剂，与镧在ｐＨ＝２．８～３．０条件下显色，在最大吸收波长６６５ｎｍ处，测得表观摩尔吸光系数为４．８６×１０４Ｌ／（ｍｏｌ·ｃｍ），线性范围为０～３７μｇ／２５ｍｌ。方法可直接用于催化剂中镧的测定。其加标回收率为９８．４％～１０３．１％，相对标准偏差小于１．０７％，方法的准确性和精密度良好。

 method for determining lanthanum content in catalysts with spectrophotometric method is propose in this paperASN(Ⅲ) is selected as the chromogenic reagent to form a purple complex with La3+at pH 28～30 The molar absorptivity is 486×104 at 665nmBeers law is obeyed in the range of 0～37μg/25ml for lanthanumThe interference of 15 kinds of metallic ions are inspected and the method to eliminate interference is suggestedThe content of lanthanum in catalysts was determined directly by this method with a relative standard deviation of lower than 107%The recoveries were 984%～1031% The method is convenient and both precision and accuracy are satisfactory