Capillary electrophoresis with diode array detection for the determination of organic acids in fermented food samples.

Short-chain fatty acids (SCFAs), branched SCFAs, and their precursors (lactic, succinic, pyruvic acids) are key microbial metabolites relevant to gut function and are present in fermented foods. This study reports the transfer, development, and validation of a rapid capillary electrophoresis method with diode-array detection (indirect UV) for the simultaneous determination of 12 biologically important organic acids in <15 min. Starting from a commercial methodology, background electrolyte composition and separation voltage were optimised. The method was validated according to ICH Q2(R2). Linearity was confirmed from LOQ to 100 μg/mL, with LOQs of 1.53-5.76 μg/mL. Precision and trueness were satisfactory (CV ≤ 7.6%, |RE| ≤ 7.5%), matrix effects ranged from 80 to 121%, and selectivity was adequate. Applicability was demonstrated by analysing 11 fermented vegetable juices. Finally, the RGBfast model benchmarking against literature methods supported the method's suitability for routine profiling of organic acids in fermented foods.