An isocratic liquid chromatographic method for the determination of ascorbic acid (vitamin C) is described. The separation was performed on a C18 reversed-phase column with isocratic elution using phosphate buffer / methanol as a mobile phase. The photodiode array detector used was set at a wavelength of 245 nm. The limit of detection and determination was estimated at 0.23 mg/L and 0.46 mg/L per 50 μL injection. Ascorbic acid contents of freeze dried carrots, fresh squeezed lemon and grapefruit juices were analysed comparatively by liquid chromatography and by the AOAC official titrimetric method. Both methods gave similar results for each of the matrices analysed.

Keywords: ascorbic acid, liquid chromatography

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