Extraction and ESI–CID–MS/MS analysis of myoglobins from different meat species

Meat speciation methods for raw meats are available but are not always effective in cooked products. The globin protein from myoglobin is heat stable, shows different molecular weights for each species and electrospray mass spectrometry (ESI–MS) can partially differentiate some species. To improve the analysis, the heat stable globin protein was extracted and subjected to fragmentation by ESI–CID–MS/MS. The [M+16H]16+ and [M+17H]17+ ions were chosen as precursor ions and fragmented by collision-induced dissociation (CID). Fragmentation occurred at proline residues with cleavage either side of the peptide bond leading to the typical pattern of peptide ions. The patterns were dominated by a series of y″n fragments of which the fragments from cleavage of the His/Pro residues at 119/120 (y″34 and y″35) were relatively intense. A strategy for differentiating the four species by ESI–MS and ESI–CID–MS/MS is discussed.