Determination of Ascorbyl Palmitate and Ascorbyl Stearate in Foods by LC-MS/MS.

Background: Ascorbyl palmitate (AP) and ascorbyl stearate (AS), together called ascorbyl esters, are antioxidants that are used as food additives to prolong the shelf-life of foods by protecting against deterioration caused by oxidation.

Objective: This paper aimed to develop a simple solvent extraction and LC-MS/MS method for the determination of AP and AS in a broad range of food matrices.

Methods: AP and AS in foods were extracted with methanol containing 0.5% (w/v) L-ascorbic acid and analyzed by liquid chromatography-tandem mass spectrometer in negative electrospray ionization and multiple reaction monitoring (MRM) mode.

Results: The method was able to quantitatively detect AP and AS in different food matrices (canned drink, dessert, frozen fish, herbs, oils and infant formula/formulated products, etc) with recoveries of AP and AS at 73-113% and 75-113% respectively and the corresponding relative standard deviations (RSDs) of 0.3-16.1% and 0.2-13.7%. The limits of quantitation were 0.23 mg/kg for AP and 0.14 mg/kg for AS. Method applicability was also demonstrated by the detection of AP in powdered infant formula purchased from local market.

Conclusion: A simple solvent extraction and LC-MS/MS method was developed, validated and demonstrated for the quantitative determination of AP and AS in various foods.

Highlights: The validated method based on solvent extraction with LC-MS/MS detection offered a fast and simple method for the analysis of AP and AS in a wide range of foods.