Determination of Vitamins A, D and E in Health Foods Using Column-Switching Liquid Chromatography

A method for the determination of vitamins A (VA), D (VD) and E (VE) in health foods by column-switching two-dimensional liquid chromatography was established. According to the sample pretreatment method specified in the national standard GB 5009.82-2016, VA and four isomers of VE were separated on an Agilent Poroshell 120 PFP column (4.6 mm × 100 mm, 2.7 μm) as one-dimensional chromatographic column using a mobile phase consisting of methanol and water by gradient elution, and VD₂ and VD₃ were separated on an Agilent Zorbax Eclipse PAH column (2.1 mm × 100 mm, 3.5 μm) by gradient elution using a mobile phase composed of methanol and acetonitrile. VD was captured on an Agilent Poroshell 120 EC C₁₈ column (4.6 mm × 5 mm, 4 μm). According to the peak time of VD on the one-dimensional chromatographic column, the column switching time was determined. The one-dimensional detection wavelengths were 325 and 294 nm, and the two-dimensional detection wavelength was 264 nm. The analytes were quantified by external standard method. Results indicated that the calibration curves were linear in the range of 2.50-50.0 μg/mL for VA, and 0.10-2.00 μg/mL for VD, and 5.00-100.0 μg/mL for VE, and the correlation coefficients were all more than 0.999. The recoveries were 86%–102%, with relative standard deviations (RSD) of 1.5%–4.0%. The results suggest that the developed method is accurate and suitable for the determination of VA, VD and VE in health foods.