Determination of phenolic preservatives in gelatin and vacant capsules for medicine use by ion-suppression reversed-phase high performance liquid chromatography

A reliable method for the simultaneous determination of phenolic preservatives parahydroxybenzoic acid, methyl, ethyl, propyl, butyl and pentyl parahydroxybenzoates in gelatin and vacant capsules for medical use has been developed by ion-suppression reversed-phase high performance liquid chromatography. Separation was carried out on a Kromasil C18 column by isocratic elution using methanol-perchloric acid (pH 2.0; 10 mM) (60:40, v/v) at a flow-rate of 1.0 ml min−1, and detection by UV absorbance at a wavelength of 254 nm. This method has been successfully applied to the routine analyses of these preservatives in the real samples.