Quantitative Analysis of Astaxanthin in Dietary Supplements by UltraPerformance Convergence Chromatography (UPC2)

Significance of the topic

Dietary supplements containing astaxanthin require precise quantification due to regulatory demands and the compound's potent antioxidant properties.
Rapid, selective methods can improve quality control throughput and ensure label claims are met.

Objectives and Study Overview

• Develop a fast and reliable UltraPerformance Convergence Chromatography (UPC2) method for quantifying free astaxanthin in supplement formulations.
• Compare UPC2 performance with existing HPLC-based approaches.
• Validate method precision, repeatability, and accuracy by assaying commercial products.

Methodology and Instrumentation

• Sample Preparation
  • Hydrolysis of astaxanthin esters using cholesterol esterase.
  • Extraction into hexane, nitrogen drying, and reconstitution in acetone.
  • Internal standard: trans-β-apo-8′-carotenal.
• Chromatographic Conditions
  • ACQUITY UPC2 HSS C18 column (3×150 mm, 1.8 μm).
  • Mobile phase: supercritical CO2 (A) and methanol (B) gradient (5–15 % B in 2 min, total run ~5 min).
  • Flow rate: 1.0 mL/min; backpressure: 200 bar; temperature: 30 °C; injection volume: 2 μL.
  • Detection: PDA at 457 nm (reference 530–600 nm).

Main Results and Discussion

• Separation Efficiency: UPC2 resolved trans, 9-cis, and 13-cis astaxanthin isomers plus internal standard in ~2.2 min, vs. 35 min for conventional HPLC.
• Precision: Intra-day RSDs <3.7 % (maximum for 13-cis isomer); inter-day RSDs <5 %.
• Supplement Assay: Three commercial products yielded % label claims within ±5 % and RSDs <1.5 %.
• Method Advantages: Simplified two-component mobile phase, reduced solvent costs, and superior throughput.

Benefits and Practical Applications

• High-throughput quality control for nutraceutical manufacturers.
• Reduced analysis time and solvent consumption enhances laboratory productivity and sustainability.
• Robust quantitation suitable for regulatory compliance and label verification.

Future Trends and Applications

• Integration of UPC2 with mass spectrometry for enhanced structural confirmation.
• Expansion to other non-polar natural products and carotenoid-based supplements.
• Development of automated sample prep and greener mobile phase strategies.
• Advances in stationary phase chemistry to further improve resolution and robustness.

Conclusion

The UPC2-based method delivers rapid, precise, and reliable quantitation of astaxanthin in dietary supplements, outperforming traditional HPLC in speed and operational simplicity. Its adoption can streamline routine quality control workflows and satisfy increasingly stringent regulatory requirements.

References

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