[Studies on the separation and determination of natural phenolic acids by reversed-phase high performance liquid...

A new method using gradient elution of reversed-phase high performance liquid chromatography was set up for the separation and determination of 12 natural phenolic acids simultaneously. The separation conditions were studied with a Zorbax ODS (5 microns) column, and optimized conditions were suggested with the mobile phase gradient elution of CH3CN-H2O (with 0.5% HAc) (5:95-->35:65, V/V, in 40 min) at room temperature, flow rate at 1.0 mL/min and detection wavelength at 280 nm. And the effects of acidity on separations and the relationships between the phenolic acids structures and their retention behaviors were discussed. Qualitative and quantitative analysis of the 12 compounds were performed. The regression equation, correlation coefficient, linear range, detection limit and relative standard deviation (RSD) of each compound were obtained under the optimized conditions. The correlation coefficients of the 12 compounds were between 0.9980 and 0.9999. The detection limits ranged from 0.96 ng to 4.10 ng and RSDs were < or = 2.64%. These results demonstrate that the optimized determination method obtained is successful for the separation and determination of the 12 phenolic acids analysed.