薄层色谱-苯酚硫酸法分析大豆低聚糖中棉籽糖含量

目的：采用比色法建立一种适用于大豆低聚糖中棉籽糖快速检测的方法。方法：运用薄层层析技术分离单糖与低聚糖，展开剂为V(乙腈):V(冰乙酸):V(水)=6:3:2，显色剂为苯胺- 二苯胺- 磷酸，点样量为5μL，层析显色后，苯酚- 硫酸法比色测定。结果：薄层层析可将大豆低聚糖中蔗糖、棉籽糖和水苏糖等组分分开，通过苯酚- 硫酸法分析其中的棉籽糖，线性范围为20～80mg/mL(R2=0.9932)，精密度RSD 为1.56%，平均加样回收率为98.14%，RSD 为3.99%。结论：以薄层层析- 苯酚- 硫酸法检测食品或大豆低聚糖中棉籽糖含量，测定结果与HPLC 法对照，相对误差为3.22%，可用于大豆低聚糖中棉籽糖的检测。

Combination of Thin-layer Chromatography with Phenol-sulfuric Acid Method for Analyzing the Content of Raffinose in Soybean Oligosaccharide

Objective: To establish a method for the fast determination of raffinose in food and oligosaccharide by the combined use of thin layer chromatography (TLC) and phenol-sulfuric acid method. Methods: For the separation of raffinose, the developing solvent used was a mixture of methyl cyanides, acetic acid and water (6:3:2, V/V), and the chromogenic agent was composed of aminobenzene, diphenylamine and phosphoric acid, and the sample loading volume was 5 μL. The separated raffinose brand was harvested and analyzed by phenol-sulfuric acid method. Results: Different components of soybean oligosaccharide (sucrose, raffinose and stachyose) could be well separated by using TLC. The standard curve developed for raffinose determination by phenol-sulfuric acid method presented a linear range from 20 to 80 mg/mL (R2 = 0.9932). The precision RSD for raffinose determination was 1.56%. The method spike recovery was 98.14%, with a RSD of 3.99%. The relative error between the results of determination by this method and HPLC was 3.22%. This method is applicable to the determination of raffinose in food and oligosaccharide.