Determination of Gluten by UHPLC−MS/MS Based on Peptide Marker Summation for the Account of the Genetic Variability

A procedure is developed for determining gluten in commercial food products using ultra-high-performance liquid chromatography−tandem mass spectrometry. A key feature of the procedure is minimizing the impact of variations in the gluten protein content and composition on the result of quantitative analysis, achieved by summing the responses of several marker peptides. The results show that the overall limit of detection by the developed procedure is 10 mg/kg of gluten proteins in food products. It is shown that an increase in the number of marker peptides improves the reliability of the method in analyzing food products with varying gluten protein compositions. This approach ensures an improvement in the accuracy of the control of gluten content, which is important for the products labeled “gluten-free.”