Improved Determination of Antioxidants in Edible Oils Using Solid Core LC Columns

Importance of the Topic

Phenolic antioxidants play a critical role in preserving edible oils by inhibiting oxidative rancidity. Accurate quantification of these compounds in complex food matrices is vital for regulatory compliance and ensuring product quality.

Objectives and Study Overview

This study evaluates the performance of Thermo Scientific Accucore C18 and Accucore Polar Premium solid core LC columns for the determination of twelve synthetic and natural antioxidants in edible oil samples according to AOAC Method 983.15. The goal is to improve selectivity and overcome matrix interferences.

Methodology and Instrumentation

Sample preparation followed AOAC 983.15: fat-rich food samples were warmed, extracted with heptane, then partitioned into acetonitrile. After evaporation and reconstitution, analytes were separated by HPLC using:

• Thermo Scientific Dionex UltiMate 3000 system (LPG-3400RS pump, WPS-3000RS autosampler, DAD-3000RS detector, TCC-3000RS oven)
• Accucore C18, 2.6 μm, 100×3 mm and Accucore Polar Premium, 2.6 μm, 100×3 mm columns
• Gradient elution with acetonitrile/methanol/acetic acid (49.25:49.25:0.5) and water/acetic acid (99.5:0.5)
• Flow rate 0.80 mL/min, column temperature 30 °C, injection volume 2 μL, UV detection at 280 nm

Main Results and Discussion

Both columns achieved baseline separation of all twelve antioxidants in standard mixtures. The Accucore C18 column experienced co-elution of propyl gallate with an unknown margarine component, whereas the Accucore Polar Premium column resolved this interference, confirming assay accuracy. TBHQ was successfully quantified at 180 μg/g in margarine with both columns. Selectivity differences highlight the importance of column choice for rugged analysis.

Benefits and Practical Applications

Implementing solid core LC columns enhances robustness and throughput of antioxidant assays in food testing laboratories. The availability of multiple qualified column chemistries allows analysts to tailor methods to specific sample matrices, reducing false positives and improving data confidence.

Future Trends and Applications

Emerging solid core phases with tailored selectivity, integration with mass spectrometric detection, and development of greener mobile phases will further advance routine screening of antioxidants. Method extensions may include novel natural antioxidants and real-time monitoring in processing lines.

Conclusion

Thermo Scientific Accucore C18 and Polar Premium solid core columns are well-suited for AOAC 983.15, offering efficient, high-resolution separation of antioxidants in complex edible oil matrices. Qualification of multiple column types strengthens method resilience against matrix interferences.

Reference

• US Food and Drug Administration, 21CFR172 Subpart B (Preservatives).
• D.L. Madhavi, S.S. Deshpande, D.K. Salunkhe, Food Antioxidants: Technological, Toxicological and Health Perspectives, Marcel Dekker, Inc., NY, 1996.
• AOAC Official Methods of Analysis, Method 983.15, Phenolic Antioxidants in Oils, Fats and Butter Oil, 1994.