Two-dimensional HPLC determination of water-soluble vitamins in a nutritional drink

Significance of the Topic

Accurate determination of water-soluble vitamins in complex nutritional drinks is critical for quality control and regulatory compliance. Traditional single-dimension HPLC methods often fail in samples containing proteins, minerals, botanical extracts, and other additives due to coelution and matrix interferences. An efficient two-dimensional HPLC (2D-HPLC) approach addresses these challenges by combining different column chemistries and heart-cutting techniques to improve selectivity and sensitivity.

Objectives and Study Overview

The primary objective was to develop a robust, sensitive, and automated 2D-HPLC method for simultaneous quantification of seven B-group vitamins (B1, B2, B3, B5, B6, B7, B12) and vitamin C in a nontransparent multivitamin/mineral drink. The study assessed method reproducibility, linearity, detection limits, and accuracy in spiked and commercial samples.

Methodology and Instrumentation

Sample Preparation:

• Dilute or filter the drink sample with deionized water and store at 4 °C in amber vials.
• Prepare individual and mixed vitamin stock solutions in deionized water; adjust concentrations to ensure solubility (e.g., VB2 at 0.03 mg/mL).
• Mix aliquots to yield working standards spanning calibration ranges (0.1–100 μg/mL).

2D-HPLC Configuration:

• System: Thermo Scientific UltiMate 3000 Dual-Gradient RS LC with integrated degasser, dual pumps, thermostatted column compartment, split-loop autosampler, and diode array detector.
• First Dimension Columns:
  
  • Acclaim PolarAdvantage (PA), 5 μm, 4.6×250 mm for vitamins B1–B7, VC.
  • Hypersil GOLD Phenyl, 5 μm, 4.6×150 mm for vitamin B12.
• Second Dimension Column: Acclaim 120 C18, 5 μm, 4.6×150 mm.
• Mobile Phases: 25 mM potassium phosphate buffer (pH 3.0) and acetonitrile, with gradient elution and timed valve switching for heart-cutting transfers. A 750 μL mixer dilutes fractions rich in organic solvent prior to the second column.
• Detection: UV absorbance at multiple wavelengths (210, 245, 268, 291 nm).

Main Results and Discussion

• Valve switching and mixer integration enabled clean transfer of early and late eluting fractions without an additional pump. Final configuration achieved baseline separation for all target vitamins.
• Reproducibility: Retention time RSD ≤0.11% and peak area RSD ≤3.44% over eight injections.
• Linearity: Calibration curves were linear (r ≥0.9978) over vitamin-specific ranges; method detection limits ranged from 0.03 to 1.5 μg/mL.
• Sample Analysis: Vitamins B1, B2, B5, B6, C were detected near labeled values with recoveries of 95–115% in spiked samples. Vitamins B3, B7, and B12 were below detection or absent at sample levels, but spiking confirmed method capability.

Benefits and Practical Applications

This 2D-HPLC method streamlines analysis of complex beverage matrices with minimal manual sample cleanup, fully automated separation steps, and robust quantification. It supports routine quality control in nutraceutical, food, and beverage industries, reducing analysis time and improving data reliability for multivitamin formulations.

Future Trends and Opportunities

Upcoming developments may include coupling 2D-HPLC with mass spectrometry for enhanced selectivity, expanding to trace-level analysis of additional micronutrients, and integrating advanced software for real-time method optimization. Miniaturized columns and rapid gradient systems could further increase throughput and reduce solvent consumption.

Conclusion

The developed 2D-HPLC method provides a simple, sensitive, and reproducible approach for simultaneous determination of multiple water-soluble vitamins in complex nutritional drinks. It overcomes limitations of conventional HPLC, offering improved resolution and quantitative accuracy, and is readily adaptable for quality assurance in industrial laboratories.

Reference

• Moreno P.; Salvado V. Determination of Eight Water- and Fat-Soluble Vitamins in Multivitamin Pharmaceutical Formulations by High-Performance Liquid Chromatography. J. Chromatogr. A 2000, 870, 207–215.
• Perveen S.; Yasmin A.; Khan K.M. Quantitative Simultaneous Estimation of Water Soluble Vitamins, Riboflavin, Pyridoxine, Cyanocobalamin and Folic Acid in Nutraceutical Products by HPLC. Open Anal. Chem. J. 2009, 3, 1–5.
• Thermo Fisher Scientific Application Note 252: HPLC Assay of Water-Soluble Vitamins, Fat-Soluble Vitamins, and a Preservative in Dry Syrup Multivitamin Formulation.
• Vitamins/Dietary Supplements. U.S. Pharmacopeia 35, NF 30; Rockville, MD, 2008; pp 1592–1605.
• Thermo Fisher Scientific Application Note 287: Two-Dimensional HPLC Combined with On-Line SPE for Determination of Sudan Dyes I–IV in Chili Oil; 2011.
• Thermo Fisher Scientific Application Note 72597: Determination of Sudan Dyes I–IV in Curry Paste; 2012.
• Thermo Fisher Scientific Technical Note 72488: Determination of Water- and Fat-Soluble Vitamins by HPLC; 2010.