A SILAC-based accurate quantification of shrimp allergen tropomyosin in complex food matrices using UPLC-MS/MS.

[Display omitted] • A recombinant full-length isotope-labelled tropomyosin was expressed with high purity and isotope labeling ratio. • An absolute LC-MS/MS quantification assay was developed for shrimp tropomyosin in complex food matrices. • The limits of quantification for tropomyosin were 1–10 μg/g. • This method was successfully applied to the accurate quantification of tropomyosin in real samples. The carryover of trace allergens in complex food matrices poses challenges for detection techniques. Here, we demonstrate an accurate UPLC-MS/MS quantification assay for the shrimp allergen tropomyosin with a full-length isotope-labelled recombinant tropomyosin (TM-I) internal standard in complex food matrices. The TM-I, expressed based on the SILAC technique, exhibited a high isotope labelling ratio (>99%), purity, and alignment with the natural sequence. This method determined the tropomyosin ranging from 0.2 to 100 ng/mL. Mean recoveries ranged from 89 to 116%, with intra- and inter-day RSDs below 12%, for three signature peptides across three types of commercially processed food matrices. The limits of quantitation were 1 μg/g in pop food and sauce, and 10 μg/g in surimi product, respectively. This study supports the use of recombinant full-length isotope-labelled proteins rather than stable-isotope labelling peptides as internal standards to achieve more accurate quantitation of food allergens as the digestion error is corrected. [ABSTRACT FROM AUTHOR]