Rapid Simultaneous Analysis of Vitamin A as Retinyl Palmitate and Beta Carotene Using the Agilent 1290 Infinity LC and STM Columns

Significance of the Topic

Accurate quantification of fat-soluble vitamins such as beta carotene and retinyl palmitate is essential for quality control in supplement manufacturing and nutritional analysis. Recent advances in liquid chromatography instrumentation and column technology offer opportunities to accelerate analysis times while maintaining resolution, reducing solvent consumption, and cutting operational costs.

Study Objectives and Overview

This application study evaluates a rapid LC method using the Agilent 1290 Infinity LC System coupled with STM columns, comparing it to the conventional in-house SNA method. The goal is to demonstrate an eightfold reduction in analysis time, significant solvent savings, and comparable analytical performance.

Methodology and Instrumentation

The study applied a liquid–liquid extraction procedure (USP Method II) involving DMSO and iso-octane for sample preparation, followed by isocratic reversed-phase LC separation. Key steps include:

• Shake-out extraction into iso-octane with DMSO to disrupt encapsulants
• Dilution into methanol prior to injection

Used Instrumentation

Two LC setups were compared:

• Agilent 1290 Infinity LC System with ZORBAX RRHD Eclipse Plus C18 column (2.1×50 mm, 1.8 μm)
• SNA in-house system with non-Agilent C18 column (4.6×150 mm, 3 μm)

Operating parameters for the Agilent system include 40 °C column temperature, 5 μL injection, UV-DAD detection at 460 nm (beta carotene) and 325 nm (retinyl palmitate), 1.0 mL/min flow, and a 70/30 methanol–acetonitrile mobile phase containing 3.2 g/L ammonium acetate (isocratic). The SNA method used similar detection wavelengths, a 20 μL injection, 1.5 mL/min flow, and identical mobile phase composition.

Main Results and Discussion

The Agilent-based method resolved beta carotene and retinyl palmitate in under 3 minutes, compared to approximately 19 minutes for the SNA protocol. Chromatograms demonstrated clear peak separation and high linearity (R² > 0.9999) over relevant concentration ranges. The reduced cycle time translates directly to higher sample throughput and lower reagent usage.

Benefits and Practical Applications

This optimized LC approach offers:

• Eightfold faster analysis time
• Substantial solvent consumption reduction
• Maintained chromatographic resolution and quantitative accuracy
• Improved laboratory productivity and cost efficiency

Future Trends and Potential Applications

Further integration of sub-2 μm stationary phases with ultra-high-pressure LC systems is expected to push analysis times even lower. The approach can be adapted to other fat-soluble vitamins and lipophilic analytes in food, pharmaceuticals, and clinical diagnostics. Ongoing developments in column chemistries and detectors will expand multiplexed nutrient profiling capabilities.

Conclusion

The Agilent 1290 Infinity LC with STM columns enables rapid, reliable quantification of beta carotene and retinyl palmitate, delivering substantial time and solvent savings without compromising performance. This method represents a robust solution for high-throughput vitamin A analysis.

Reference

1. United States Pharmacopeia. Fat Soluble Vitamins, Method 2; USP36/NF31: p. 1632.
2. Wikipedia contributors. Beta-Carotene. Wikipedia, 27 June 2013.
3. Wikipedia contributors. Retinyl palmitate. Wikipedia, 30 May 2013.