title: Determination of osteocalcin in meat and bone meal of bovine and porcine origin using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry and high-resolution hybrid mass spectrometry.
abstract: A method has been developed for determining the origin of meat and bone meal (MBM) by detecting species-specific osteocalcin (OC) using matrix-assisted laser desorption ionization/time-of-flight (MALDI/TOF) and high-resolution hybrid mass spectrometry (HR-Q/TOF MS). The analysis is based on the detection of typical species-specific OC and its tryptic peptide fragments which differ in mass due to differences in the amino-acid sequences between species. After dissolving the MBM samples in EDTA buffer, purification after ultrafiltration was performed using two methods: solid-phase extraction using Zip-Tip C(18) or size exclusion coupled with reverse-phase chromatography. Fractions containing partially purified intact OC were analyzed using LC-Q/TOF and MALDI/TOF mass spectrometry. Species-specific OC was detected at the typical protonated and doubly protonated molecular ions. Furthermore, typical porcine- and bovine-derived tryptic fragments from MBM were detected after enzymatic digestion. In order to determine the underlying amino-acid sequences and to confirm the assignment to OC-derived peptides, MS/MS analysis was carried out. In conclusion, we were able to detect OC in bovine and porcine MBM with high sensitivity and the MS-based method described here by which total OC mass and marker peptides of digested OC are recorded can be used as an alternative approach to detect genus-specific differences in MBM and can be applied as a confirmatory method to mainly immunological osteocalcin screening methods.
authors.affiliation: Federal Institute for Risk Assessment, Berlin, Germany. gabor.balizs@bfr.bund.de
authors.forename: Gabor
authors.initials: G
authors.lastname: Balizs
authors.forename: Christoph
authors.initials: C
authors.lastname: Weise
authors.forename: Christel
authors.initials: C
authors.lastname: Rozycki
authors.forename: Tobias
authors.initials: T
authors.lastname: Opialla
authors.forename: Stefanie
authors.initials: S
authors.lastname: Sawada
authors.forename: Jutta
authors.initials: J
authors.lastname: Zagon
authors.forename: Alfonso
authors.initials: A
authors.lastname: Lampen