Determination of organic acids in fermented fluid of lactic acid bacteria by capillary electrophoresis

The capillary electrophoresis conditions for the determination of 8 organic acids,including lactic acid,citric acid,pyruvate,isocitric acid,malic acid,α-ketoglutaric acid,fumaric acid and oxalic acid were investigated.The optimized running buffer contained 300 mmol/L phosphate,0.5 mmol/L hexadecyl trimethyl ammonium bromide and 18%(vol) methanol with pH 8.0.Sample was injected at 50 mbar for 50 s,followed by separation at-15 kV and 20 ℃ and detection at 200 nm.The relative standard deviations of migration time and peak area were less than 0.5% and 10%,respectively.The spiked recovery rate ranged between 81.4% and 108.5%.The established method was suitable to profile organic acids produced by lactic acid bacteria due to its simplicity,high efficiency and great accuracy.