Detection of the organic acids in bacterial metabolites by high-performance capillary electrophoresis

Objective To establish a method for determining formic acid,acetic acid,propionic acid,butyric acid and lactic acid in bacterial metabolites by the high-performance capillary electrophoresis.Methods Samples were analyzed on a Beckman Coulter(50 μm ×50 cm) uncoated fused-silica capillary using 10 mmol/L borate buffer(pH 10.5,containing 0.5 mmol/L CTAB).The UV detection wavelength was 214 nm,the separation voltage-20 kV and injection pressure 1.0 psi×10 s.Results Standard samples of formic acid,acetic acid,propionic acid,butyric acid and lactic acid were separated well in 4 minutes,and their linear ranges were 3.8-30.7 mg/L(r=0.997 1),3.3-52.5 mg/L(r=0.996 1),3.1-49.5 mg/L(r=0.999 3),3.0-48.0 mg/L(r=0.992 5),7.5-60.5 mg/L(r=0.999 5),respectively,their average recoveries were 99.29%,98.90%,99.65%,99.35% and 98.06%,respectively.The RSD values(n=6) of formic acid,acetic acid,propionic acid,butyric acid and lactic acid were 0.67%,1.36%,0.65%,0.42%,1.44%,respectively.Conclusion The method is simple,rapid and accurate for detecting the organic acids in bacterial metabolites in fermentation liquor.