determination of carboxylic acids in apple juice by rp hplc

low molecular weight organic acids are most predominant in apple juice among these components fumaric acid was not exceed more than 5 ppm. it was thought that the hplc is the best method of the determination of organic acids in the apple juice. in this study, chromatographic separation of organic acids of apple juice was obtained by preparing a sample and by applying them to acid phase for extraction and various organic acids content of apple juice, fumaric acid, oxalic acid, tartaric acid and shikimic acids were commented as qualitative and quantitative, too.the organic acids, of which the chromatographic separations were examined, were the acids of fumaric acid, oxalic acid, tartaric acid, ascorbic acid, lactic acid, malic acid, succinic acid and shikimic acid. for this separation, the suitable value are determined by regulating the ph of mobile phase with phosphoric acid in range of pka ±1.5 (this is the space in which the capacity factors are effectively changed). the concentration of juice was distilled to 11.2 brix and same ph was applied to cartridge by adjusting with the phosphate buffer at 8.00, and the cartridge was washed with the same buffer and the phase was combined with the first eluant. a suitable distilled percentage of samples were injected and injection volume were determined. in this study, the cartridges of supelco c18 and waters c18 were used, datas obtained by both types of cartridges were compared. in this study, the methods of external calibration and added method of standards were applied and slopes were compared.