Ascorbic acid is a vital vitamin for humans. It also serves as an antioxidant. Dehydroascorbic acid is an oxidation product of ascorbic acid. Both molecules are very polar, and cannot be retained by reverse-phase mechanism. Generic method for HPLC separation of ascorbic and dehydroascorbic acid was developed on a Primesep SB mixed-mode HPLC column. Both compounds are well separated and produce excellent peak shape. Method can be used for analysis of both compounds in biofluids. Proteins from biofluids will not retain due to repulsion effect of the stationary phase. Compounds can be monitored by common detection techniques like UV, ELSD, CAD, and LC/MS.

HPLC method for separation of active ingredients of drug/supplemental composition was developed on an Obelisc R trimodal HPLC column. Compounds are retained by combination of reversed-phase, cation-exchange and anion-exchange mechanisms. Compounds are well separated, and method can be used for quantitation of pyridoxine, ascorbic acid, niacinamide, pantothenic acid, caffeine and riboflavin in a mixture or as separate compounds in various complex mixtures. Various detection techniques can be applied for quantitation (ELSD, UV, LC/MS, Corona). This HPLC method can be adopted as general approach for analysis of active drug components in various formulations.

Mixed-mode HPLC columns allow for separation of compounds with drastically different properties. In this application, highly hydrophilic ascorbic acid is retained and separated from highly hydrophobic retinol and Vitamin E Acetate. Ascorbic acid is retained by anion-exchange mechanism and hydrophobic compounds are retained by reversed-phase mechanism. Compounds are monitored by UV detection. Mobile phase is compatible with LC/MS and method can be used to monitor basic and acidic compounds in bio-fluids (serum, blood, urine, saliva, etc.)

Organic acids were separated on a HILIC/cation-exchange column in HILIC/anion-exclusion mode. This column can be used for analysis of polar compounds in HILIC mode. If compounds are ionizable, additional mode of interaction can be added (cation-exchange or anion-exclusion).