过氧化氢－甲基红体系催化分光光度法测定油品中的痕量铁

Determination of Trace Iron in Petroleum Products by Catalytic Spectrophotometry of Hydrogen Peroxide-Methyl Red System

用过氧化氢－甲基红体系催化分光光度法测定油品中的痕量铁，建立了轻油消化的操作方法。轻、重油品分别经消化、灰化后可直接测定。摩尔吸收系数为５．８×１０￣５Ｌ（ｃｍ·ｍｏｌ）￣－１，最低检测限为０．０５μｇ／２５ｍｌ，加标回收率为９９．３％－１０２．５％。该法不受其他微量元素的干扰，操作简单，选择性好，灵敏度高。

The method is based on the principle that Fe(Ⅲ)can catalyze the decolorizing reactionwhich results from the oxidation of methyl red by hydrogen peroxide in dilute H_2SO_4nedium.Digestion conditions of light petroleum products are inspected.Light or heavyietroleum products are directly determined after digestion or ashing.The molar absorptivityis 5.8 × l0￣5L·cm￣-1·mol￣-1,with detection limit of 0.05μg/25ml and recovery of 99.3%-102.5%。The method has been used for determining trace iron in petroleum products withsatisfactory resuIts。