薄层色谱分离-水合茚三酮可见分光光度法测定食品添加剂中的γ-氨基丁酸

为建立一种以水合茚三酮为显色剂准确定量检测γ-氨基丁酸(γ-aminobutyric acid,GABA)的方法,本文系统研究了显色酸度、显色剂用量、加热温度和时间等显色条件对水合茚三酮与GABA显色反应的影响,并在最优条件下对该方法进行了评价。结果表明,在pH=7.0时,GABA与1.8 g·L^-1茚三酮乙醇溶液沸水浴60 min后显色稳定。显色后在567 nm处的吸光度与GABA的浓度线性关系良好(y=0.01234x-0.00113,R²=0.99983)。该方法重现性好(RSD=0.06%),准确度较高(加标回收率为95.4%~117.6%),检出限达21.6μg·L^-1,对GABA有一定的选择性。对食品添加剂中的GABA用薄层色谱分离后进行显色测定,结果满意。

Visible spectrophotometric determination of GABA in food additive using ninhydrin hydrate as chromogenic agent preceded by TLC

To establish an accurate quantitative method forγ-aminobutyric acid(GABA)using ninhydrin hydrate as chromogenic agent,the effects of chromogenic acidity,amount of chromogenic agent,heating temperature and heating time on the reaction of ninhydrin hydrate and GABA were studied systematically in this article.Furthermore,the method was evaluated under the optimized conditions.It was found that,when the acidity of chromogenic system was pH=7.0,GABA and ethanol solution of ninhydrin hydrate(1.8 g·L^-1)showed stable color after being heated for 60 min using boiling water bath.The absorbance(567 nm)of solution had a good linear relationship with the concentration of GABA(y=0.01234x-0.00113,R²=0.99983).In addition,the method was precise(RSD=0.06%),sensitive(LOD=21.6μg·L^-1),accurate(Standard Recovery was 95.4%~117.6%)and selective for GABA.The content of GABA in food additive was determined using the proposed method after being seperated using TLC,and satisfactory results were obtained.