Comparative Analysis of Cooking Oils Using a Solid Core HPLC Column

Significance of the Topic

The detailed lipid profile of cooking oils is critical for quality control, nutritional labeling, and fraud detection in the food industry. High-resolution chromatographic methods enable separation of triglyceride isomers and minor constituents that influence oil stability, flavor, and health attributes.

Objectives and Study Overview

This study compared the separation performance of solid core Accucore C30 and Accucore C18 columns for profiling various cooking oils. The aim was to demonstrate enhanced selectivity and resolution of long-chain hydrophobic lipids using the C30 phase under isocratic conditions.

Methodology and Instrumentation

Sample Preparation

• Vegetable oil standards prepared at 1 and 10 mg per mL in isopropanol.

Instrumentation

• Thermo Scientific Dionex UltiMate 3000 RS HPLC system with dual-ternary pump, split-loop autosampler, column thermostat, and charged aerosol detector.
• Columns evaluated: Accucore C30 (2.6 µm, 100 x 3 mm and 100 x 4.6 mm) and Accucore C18 (2.6 µm, 100 x 3 mm).

Mobile Phase and Flow

• Isocratic composition: 25% acetonitrile, 70% isopropanol, 5% aqueous buffer (7.7 g/L ammonium acetate, 2 g/L acetic acid, pH 5.2).
• Flow rates: 1.25 mL/min for 4.6 mm bore, 0.50 mL/min for 3 mm bore; column temperature maintained at 30 °C.
• Injection volumes: 5 µL at 1 mg/mL for larger bore, 1 µL at 10 mg/mL for smaller bore; backpressure around 338 bar.

Main Results and Discussion

Comparison of four cooking oils (canola, sesame, olive, peanut) on the C30 column revealed distinct chromatographic fingerprints, allowing clear differentiation based on retention time patterns of triglycerides. In peanut oil analysis, the C30 phase exhibited additional resolved peaks for long-chain lipids not separated on the C18 column, highlighting superior shape selectivity for molecules with alkyl chains exceeding eighteen carbons.

Benefits and Practical Applications

The C30 column method delivers rapid, high-efficiency separation of complex lipid mixtures, facilitating robust quality control and authentication in food laboratories. Its ability to resolve minor constituents supports regulatory compliance and product development in the edible oil sector.

Future Trends and Potential Applications

Integration with mass spectrometry will enhance structural identification of lipid species. Ultra-high-performance protocols and shorter run times will boost throughput. Expanding this approach to fatty acid profiling, nutraceutical research, and counterfeit detection represents promising directions.

Conclusion

Accucore C30 solid core columns provide enhanced selectivity and resolution for long-chain hydrophobic lipids compared to C18 phases. This improved separation capability supports detailed profiling of cooking oils, advancing quality assurance and analytical precision in food science.

Reference

• Tracy M and Hillbeck D. Comparative Analysis of Cooking Oils Using a Solid Core HPLC Column. Application Note 20663, Thermo Fisher Scientific, 2012.