Based on the ion association reaction between diammonium glycyrrhizinate and triphenylmethane cationic dye ethyl violet,a new method for the indirect determination of sweetener glycyrrhizic acid content by ionic association fading reaction spectrophotometry is proposed for the first time.In a Clark-Lubs buffer solution with pH 8.6,there is an ionic association reaction between diammonium glycyrrhizinate and ethyl violet,and the generated ion association compounds significantly fade the solution.The maximum absorption wavelength for fading is at 594 nm,and an indirect determination method for glycyrrhetinic acid has been established based on this.The results show that the concentration of diammonium glycyrrhizinate has a good linear relationship with the absorbance difference △A between 3.00 mg/L and 12.00 mg/L with a correlation coefficient of 0.999 5,the detection limit of 0.46 mg/L and the apparent molar absorbance coefficient of 3.20×104 L/(mol·cm).The method is successfully used for the determination of the content of commercially available herbal tea samples with the average spiked recovery rate of 97.11％～101.0％and the relative standard deviation(RSD)of the measured value of 0.59％～3.23％(n=5).This method has high sensitivity,strong specificity,is time-saving and convenient,and can be used for actual sample analysis.
关键词
甘草酸/乙基紫/褪色分光光度法/含量测定/离子缔合反应
Key words
glycyrrhizic acid/ethyl violet/fading spectrophotometry/content determination/ion association reaction
维普
万方数据