Development and validation of a method for the analysis of erythorbic acid and ascorbic acid in food for human consumption

Abstract

Antioxidants are molecules that can prevent other molecules from oxidation. They are used as food additives in all kind of foodstuffs to lengthen their period of consumption. For different meat foodstuffs, ascorbic acid (AA) and erythorbic acid (EA) are the most used antioxidants. AA is not restricted as food additive and it can be added as much as its necessary, but the use of EA as food additive in meat matrixes cannot be higher than 500 mg/Kg (MRL). Liquid chromatography (LC) is the chosen technique for the analysis of these compounds in complex matrixes. The most conventional modalities of reversed phase do not give good resolution between AA and EA. The main objective of this study is to establish a method based on liquid chromatography coupled with absorption spectrophotometry for the separation and quantification of AA and EA at concentrations near or below 500 mg/Kg. The developed method is based on hydrophilic interaction liquid chromatography (HILIC), a modality of chromatography especially suitable for very polar compounds, which use is growing in the last years but is not as stablished as reversed phase modality. Otherwise, the analytes tend to oxidise in aqueous solution. Previous studies have been carried out: stability tests to avoid degradation of AA and EA and chromatographic conditions tests to achieve the optimal conditions for the separation and quantification of both analytes. Extraction recovery, linearity, precision, trueness and uncertainty of the established method have been determined, and the results of the validation are fully satisfactory. The method allows the confirmatory analysis of the analytes from 30 mg/Kg (LOQ) to concentrations higher than 500 mg/Kg (MRL)