间苯三酚法测定玉米芯水解液中木糖含量

目的]研究玉米芯水解液中木糖含量的测定方法。方法]采用间苯三酚比色法测定玉米芯水解液中的木糖含量,并通过试验确定最佳测定条件。结果]单因素试验结果表明：木糖与间苯三酚显色液反应后,在波长554 nm处有最大吸收峰;最佳显色时间在8min;木糖浓度在5.17～48.70μg/ml范围内与吸光度呈线性关系,其R2值为0.999 1。葡萄糖的存在对间苯三酚法测定木糖基本没有影响。最佳测定条件：将5.0 ml间苯三酚显色剂加入到1.0 ml木糖溶液中1,00℃水浴加热8 min,流水冷却至室温,立即在波长554 nm下测定吸光度（A）。该方法的检测浓度范围为5.17～48.70μg/ml,玉米芯水解液样品的木糖含量为40.69 mg/ml。结论]该方法操作简单,精确度高,且测定木糖时不受葡萄糖干扰,可用于木质纤维素水解体系中木糖含量的快速、准确测定。

Determination of Xylose Content in Corncob Hydrolyzate by Phloroglucinol Method

Objective] The aim was to study the determination method of xylose content in corncob hydrolyzate.Method] The xylose content in corncob hydrolyzate was determined by phloroglucinol colorimetry and its optimum determination condition was confirmed through experiments.Result] The results of single factor experiments showed that the product from reaction of xylose and phloroglucinol chromogenic reagent showed maximal absorption peak;the optimum color time was 8 min;when the xylose content was in 5.17-48.70 μg/ml,the xylose content showed linear correlation with absorbance and its coefficient of determination was 0.999 1.The existence of glucose showed scarcely influence on the determination of xylose content by phloroglucinol method.The optimum determination condition was as follows:5.0 ml phloroglucinol chromogenic reagent was added into 1.0 ml xylose solution;it was followed by heating in water bath at 100 ℃ for 8 min,then it was cooled with running water to room temperature and its absorbance A was determined at 554 nm immediately.The concn.range for determination by this method was 5.17-48.70 μg/ml and the xylose content in this sample of corncob hydrolyzate was 40.69 mg/ml.Conclusion] This method was simple to operate and possessed high precision and the disturbance from glucose could be avoided in xylose content determination.This method could be applied in the rapid and accurate determination of xylose content in hydrolyzate system of lignocellulose.