3,5-二硝基水杨酸法测定石斛多糖含量的研究

Determination of Polysacharide in Dendrobium by 3,5 - Dinitrosalicylic Acid Colorimetry

目的建立石斛中多糖的含量测定方法。方法采用单因素试验对3,5-二硝基水杨酸法(DNS法)的各影响因素进行考察,确定最佳测定条件;并对不同品种石斛中多糖含量进行比较。结果确定的DNS比色法的最佳检测波长510nm,显色剂用量5.0 ml,沸水浴中保持5 min。吸光度与葡萄糖含量呈良好线性关系,线性范围为0.075 9～0.177 1 mg/ml,r=0.999 3,加样回收率为97.88%～101.28%。不同品种石斛中糖类成分含量有较大差异。结论所建立的方法稳定、可靠、重现性好,可用于石斛药材质量控制。

Objective To establish the method of 3,5 -dinitrosalicylic acid （DNS） for detecting the polysaccharide in Dendrobiurn. Methods The content of polysaccharide in Dendrobium was determined by 3,5 - dinitrosalieylic acid （DNS） colorimetry and its optimum determination conditions were confirmed through single factor experiments. Compare the content of polysaccharide between different varieties. Results It was suggested that the best suitable wavelengths for determination is 510 nm, and the best suitabale amount of color reagent is 5.0 ml, and duration for color development in water bathe is 5 min. The calibration curve was in good lineafity over the range of 0. 0759 -0. 1771 mg/ml,r = 0.9993,the average recovery was 97.88% - 101.28%. There is obvious difference in the content. Conclusion The established method was stable, reliable and repeatable, and can be applied for quality control of crude Dendrobium.