Jornal de Técnicas Analíticas e Bioanalíticas

Abstrato

Comparison of Various Detection Systems Coupled to High Performance Liquid Chromatography for Determination of Tocopherols in Meat. The Influence and Comparison of the Most Popular Sample Preparation Method

Szterk A, Roszko M, Najman K, Kruk M, Mroczek E, Zarodkiewicz M, Rogalski M and Waszkiewicz-Robak B

The presented data are of practical importance in terms of vitamin E determination in meat and other foodstuffs. Selection of a proper separation and detection method as well as sample preparation protocol might affect the reliability of results. Application of a sensitive method and such sample preparation procedures that do not cause significant degradation of the analyte ensures the reliability of the results. The conducted research has proved that the fluorescence detector (FLD) is the most sensitive of the detection systems tested and provides the LOD values in 3.8-38.5 ng ml-1 range. Ion trap was proved to be less a sensitive detector against vitamin E when compared to FLD. When atmospheric pressure chemical ionisation (APCI) was utilised the LOD values observed for γ- and α- tocopherole were 0.2 and 0.5 μg ml-1, respectively. However when atmospheric pressure photo/chemical ionisation (APPI/APCI) was used a significant increase in the ionization efficiency of δ-tocopherol was observed, which caused increases in the instrument sensitivity (LOD=1.0 μg ml-1). Sample preparation protocol based on extraction of the biological sample with ethanol and hexane with simultaneous change in partitioning coefficient, results in significantly higher recovery rates when compared to methods based on sample saponification and extraction with other solvents. Vitamin E contents in the tested pork samples were found to be in the 0.0-6.0 mg kg-1 range, depending on the determination method utilised.