Method Migration Of A Normal Phase HPLC Method For Tocopherols In Dietary Supplements

By Lise Gauthier, Kimberly Martin, Paula Hong

The growing popularity of dietary supplements has increased the demand for quality control measures to ensure products meet label claims. A common challenge in analyzing multi-vitamin formulations is the presence of both water-soluble and fat-soluble vitamins, which require different chromatographic techniques for accurate separation.

To address this, analysts typically employ multiple chromatographic modes. Reversed-phase (RP) or hydrophilic interaction chromatography (HILIC) are well-suited for highly polar water-soluble vitamins, while normal phase (NP) chromatography is preferred for non-polar, fat-soluble vitamins like vitamin E.

Isocratic normal phase methods, often used for vitamin analysis, can be challenging to transfer between HPLC systems due to differences in instrument design, solvent properties, and operating conditions. These factors can impact peak retention times, resolution, and overall method performance.

This study demonstrates the successful migration of a normal phase method for separating four vitamin E tocopherols from legacy HPLC systems to a modern Alliance™ iS HPLC System. The migrated method met stringent system suitability criteria, including peak area %RSD and resolution. Furthermore, it was successfully applied to the analysis of tocopherols in dietary supplements, confirming its reliability and accuracy.