Identification of meat marker peptides and detection of adulteration by liquid chromatography-tandem mass spectrometry

: A liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the identification of meat marker peptides and quantitative detection of common exogenous meat in mutton adulteration. Samples were prepared by protein extraction, trypsin hydrolysis, and solid phase extraction. Proteins and peptides were identified using ultra-performance liquid chromatography-quadrupole/electrostatic orbitrap-high resolution mass spectrometry (UPLC-Q/Exactive-HRMS) combined with Proteinpilot software. Twenty species-specificity marker peptides in mutton, duck, pork, and chicken were identified by comparison of the basic local alignment search tool (BLAST) with the Uniprot database. Verification and multiple reaction monitoring (MRM) of these marker peptides were performed quantitatively using a UPLC-triple-quadrupole mass spectrometry (QqQ-MS) system. Duck, pork, and chicken were added to mutton at mass percentages of 1%, 5%, 10%, 20%, and 50%. The limit of detection for the adulterants was 0.25% for duck, 0.17% for pork, and 0.10% for chicken.