Development of a simple and reliable high-performance liquid chromatography–tandem mass spectrometry approach to simultaneously detect grains specified in food allergen labeling regulation on processed food commodities

Abstract An analytical approach using high-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed to simultaneously detect Fagopyrum esculentum Moench (buckwheat) and cereals containing gluten (Triticum species including wheat and spelt, rye, barley, and oats) that were specified in regulations for mandatory food allergen labeling on processed foods. Trypsin-digested peptides were purified from different processed food commodities and heptapeptides derived from buckwheat 13S globulin (GFIVQAR, m/z 395.8 [precursor] > 177.0 [product]) and Triticum low molecular weight glutenin (QIPEQSR, m/z 429.3 [precursor] > 616.2 [product]) were specifically detected each species at levels as low as 0.050–0.056 µg/L and 0.028–0.032 µg/L, respectively. Detection of these synthetic peptides was quantitative to over 100 µg/L by reference to the synthetic peptide calibration curves and at recovery rates, 76.6 ± 4.1%–104.8 ± 17.1% and 82.4 ± 2.0%–105.8 ± 5.3%, for GFIVQAR and QIPEQSR, respectively, when 1–1,000 µg of these peptides were spiked into a retort tomato sauce for pasta or dried instant soup. In combination with LC–MS/MS detection methods specific to other cereals containing gluten (rye, barley, and oats), the developed analytical approach was applicable to a wide variety of processed food commodities for food allergen labeling.