Determination of Salicylic and Gentisic Acids Using HPLC-DAD Combined with Second-Order Calibration Method

Abstract

The highly overlapped chromatograms and spectra of salicylic acid (SA), gentisic acid (GA) and uncalibrated interferent, pyrocatechuic acid (PA) were resolved using HPLC-DAD combined with a novel second-order calibration method. Their elution time was set from 0.6628 min to 0.9495 min and the detection wavelength was chosen from 268 nm to 332 nm. Both SA and GA were determined simultaneously in aqueous solution with their recoveries were (101.0 ± 7.1) % and (105.8 ± 5.6) %, respectively. The satisfying results demonstrate this method can be easily performed and applied to solving second-order calibration problems quickly and accurately.