Comparative analysis of official analytical methods for tocopheryl esters for food additive quality control

Area of Science:

• Analytical Chemistry
• Food Science
• Regulatory Science

Background:

• Tocopheryl esters (vitamin E) are crucial as nutritional fortifiers and antioxidants in food products.
• Accurate quantification of tocopheryl esters is vital for regulatory compliance and quality assurance.
• Discrepancies in official analytical methods across different jurisdictions can lead to method-dependent variability.

Purpose of the Study:

• To reproduce and validate official analytical methods for d-α-tocopheryl acetate, dl-α-tocopheryl acetate, and d-α-tocopheryl succinate from Korea, China, and Japan.
• To comparatively evaluate the performance characteristics (sensitivity, recovery, precision) of different analytical principles.
• To assess measurement uncertainty associated with each method.

Main Methods:

• Reproduction and validation of official analytical procedures from Korea, China, and Japan according to ICH Q2(R1) guidelines.
• Utilized Gas Chromatography with Flame Ionization Detection (GC-FID), High-Performance Liquid Chromatography with Photodiode Array Detection (HPLC-PDA), and titration.
• Estimated measurement uncertainty using ISO GUM and Eurachem approaches with a coverage factor k=2.

Main Results:

• All validated methods met the acceptance criteria.
• Significant differences in sensitivity, recovery, and precision were observed across GC-FID, HPLC-PDA, and titration methods.
• Recoveries ranged from 86.34% to 114.86% (GC-FID), 94.13% to 99.75% (HPLC-PDA), and 99.86% to 100.45% (titration).
• Intra-day Relative Standard Deviation (RSD) was below 2.6% for all methods.
• Expanded uncertainties (U) ranged from 4.87% to 10.39%, highlighting method-specific contributions.

Conclusions:

• Methodological design significantly influences the outcomes of tocopheryl ester quantification.
• Comparative evaluation of analytical methods is essential for ensuring reliable results in food additive analysis.
• Understanding method-specific uncertainties aids in regulatory compliance and quality control for tocopheryl esters.