Determination of benzoic acid and sorbic acid in sauce by HPLC-MS

A method for determining benzoic acid and sorbic acid in sauce was developed successfully. It was based on a high performance liquid chromatogram associated with a mass spectrum. The benzoic acid and sorbic acid were separated by a C₁₈ reversed-case column, which using mobile phase consisted of CH₃OH:CH₃COONH₄ (0.02 mol/L) = 15 : 85 with a flow rate of 0.8 mL/min. The detection was performed with an ESI-mass spectroscopy (API-ES MS). The mass charge ratios of benzoic acid and sorbic acid were 121, 111. The calibration curve was well with the correlation coefficient up to 0.9900. The recoveries were beyond 95.2 % ~ 110.0 % and the relative standard deviation (RSD) was 1.25 % ~ 3.58 %. This method was a quick, simple and accurate method, and could be applied to determine benzoic and sorbic acids in sauce.