The present paper reports a novel method for the determination of silicon content in straw fibrous material black liquor based on α-Si-Mo heteropoly acid spectrophotometry. The selected conditions were as follows: detection wavelength 360 ran, pH 4.0, and reaction time 10 mia It was found that the acidic soluble lignin in the sample liquor was the major interference species in the silicon content determination. The interference of acidic soluble lignin can be eliminated by hydrogen peroxide-nitric acid digestion method. The present method is not only simple, rapid, stable and less interferential, but also of good measurement precision and accuracy, with the relative standard deviations of 0. 9%, and recoveries of 99.0%~102%. It is suitable for use in high silicon content of black liquor routine rapid analyses.%应用基于α-型硅钼黄显色的分光光度法进行草类原料蒸煮黑液中硅含量的测定.测定波长360nm,pH 4.0,时间10 min.实验中采用过氧化氢-硝酸消解法消除样品中木素成分对光度检测的干扰.研究表明:该方法的相对偏差及回收率分别为0.9％和99.0％～102％.该方法具有操作简便、快速,稳定性好,准确性高,试剂干扰少的优点,可用于黑液中高硅含量的日常快速分析.
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