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Sensitivity Intensified Ninhydrin-Based Chromogenic System by Ethanol-Ethyl Acetate: Application to Relative Quantitation of GABA

Authors :
Haixing Li
Lingqin Wang
Lijuan Nie
Xiaohua Liu
Jinheng Fu
Source :
Metabolites, Vol 13, Iss 2, p 283 (2023)
Publication Year :
2023
Publisher :
MDPI AG, 2023.

Abstract

Gamma-aminobutyric acid (GABA) is a functional metabolite in various organisms. Herein, a sensitivity intensified ninhydrin-based chromogenic system (SINICS), achieved by ethanol and ethyl acetate, is described for the reliable relative quantitation of GABA. A 2.9 mL SINICS kit comprises 1% ninhydrin, 40% ethanol, 25% ethyl acetate, and 35 μL 0.2 M sodium acetate buffer (pH 5.0). In practice, following the addition of a 0.1 mL sample to the kit, the chromogenic reaction is completed by heating at 70 °C for 30 min. The kit increased the color development sensitivity of L-glutamic acid and GABA, with the detection limits being reduced from 20 mM and 200 mM to 5 mM and 20 mM, respectively. The chromophore was stable for at least 2 h at room temperature, which was sufficient for a routine colorimetric analysis. The absorbance at 570 nm with the deduction of background directly represents the content of amino acid. For a proof-of-concept, the SINICS was adopted to optimize the GABA fermentation process of Levilactobacillus brevis CD0817. The results demonstrated that SINICS is an attractive alternative to the available ninhydrin-based colorimetric methods.

Details

Language :
English
ISSN :
22181989
Volume :
13
Issue :
2
Database :
Directory of Open Access Journals
Journal :
Metabolites
Publication Type :
Academic Journal
Accession number :
edsdoj.88ef256af8ca4c27b576678e8d78982c
Document Type :
article
Full Text :
https://doi.org/10.3390/metabo13020283