Monitoring Antioxidant Additives in Foods, Using HPLC or Capillary GC and a New Reference Standards Kit

Significance of the Topic

Food spoilage by lipid oxidation compromises nutritional value, color and aroma, leading to economic loss and health concerns. Phenolic antioxidants are widely used to inhibit free radical formation and slow rancidity in oils, fats and food products. Reliable monitoring of these additives ensures consistent quality, regulatory compliance and consumer safety.

Objectives and Overview of the Study

This article introduces a comprehensive reference standards kit for the nine phenolic antioxidants defined by AOAC Official Method 983.15, plus ethoxyquin. It demonstrates rapid HPLC separation on SUPELCOSIL LC-18 and evaluates capillary GC on SAC-5 for selected antioxidants, highlighting analytical performance and practical utility.

Methodology and Instrumentation

Analyses employed:

• HPLC: SUPELCOSIL LC-18 columns (15 cm or 25 cm × 4.6 mm, 5 µm), gradient elution from 30% to 100% organic (acetonitrile:methanol 50:50) in 10 min, UV detection at 280 nm.
• GC: SAC-5 capillary column (30 m × 0.25 mm, 0.25 µm film), isothermal at 200 °C, FID detection.

Main Results and Discussion

HPLC achieved baseline resolution of all nine AOAC antioxidants in under 13 minutes on the 15 cm column, with only a slight retention increase on the 25 cm column. Ethoxyquin is not UV-active at 280 nm and thus excluded from the HPLC chromatogram. GC analysis provided good separation for seven antioxidants, including ethoxyquin, but high-boiling compounds such as lauryl and octyl gallate eluted poorly under the chosen conditions. The standards kit packaging under nitrogen ensures stability and convenience for routine analysis.

Benefits and Practical Applications

• Single-source kit delivers all required phenolic standards and ethoxyquin, simplifying procurement.
• Time-efficient HPLC method compatible with existing AOAC protocols.
• GC option allows alternative analysis for suitable analytes.
• Wide applicability in food, beverage and quality control laboratories.

Future Trends and Applications

Emerging techniques such as LC-MS/MS and UHPLC promise enhanced sensitivity and throughput. Miniaturized and on-line sensors may enable real-time monitoring of antioxidants in complex food matrices. Customizable standard mixes and hyphenated methods will support regulatory updates and novel antioxidant chemistries.

Conclusion

The Supelco AOAC Antioxidant Standards Kit offers a robust solution for routine monitoring of key phenolic antioxidants in food systems. Combined with validated HPLC and GC procedures, it ensures accurate, rapid and comprehensive analysis to support quality assurance and regulatory compliance.

Reference

1. AOAC Official Methods of Analysis, 16th Edition, Method 983.15: Phenolic Antioxidants in Oils, Fats, and Butter Oil, Association of Official Analytical Chemists, Arlington, VA, 1995.