Derivatization-free quantification of L-glutamic acid in commercial chips and sauces via capillary electrophoresis with contactless conductivity detection

Increasing awareness of the excessive use of food additives has led researchers to develop rapid and reliable analytical methods applicable to complex food matrices. Monosodium glutamate (MSG) is widely used as flavor enhancer, responsible for the characteristic umami taste, and their use is regulated by food safety authorities. In this study, a rapid, sensitive, derivatization-free capillary electrophoresis method coupled with capacitively coupled contactless conductivity detection (CE-C⁴D) was developed using 50 mM 3-(N-Aminopropyl)amino-2-hydroxypropanesulfonic acid/Tris and 0.2 mM cetylpyridinium bromide at pH 8.5 for the determination of L-Glutamic acid in commercial sauces and chips. The proposed method achieved a limit of detection of 0.05 mg/L with a total analysis time of less than 3 min. The method was applied to real food samples and validated for greenness, linearity, sensitivity, precision, accuracy, and resistance to matrix effects. Recoveries ranged from 83.2 to 101%, demonstrating the applicability for routine analysis of processed food samples.