title: Determination of vitamin B12 in milk products and selected foods by optical biosensor protein-binding assay: method comparison.
abstract: Biomolecular interaction analysis was evaluated for the automated determination of vitamin B12 in a range of foods. The analytical technique was configured as a biosensor-based, nonlabeled inhibition protein-binding assay using nonintrinsic R-protein. Sample extraction conditions were optimized, and both ligand specificity and nonspecific binding considerations were evaluated. Performance parameters included a quantitation range of 0.08-2.40 ng/mL, recoveries of 89-106%, agreement against assigned reference values for 3 independent certified food reference materials, and a mean between-laboratory reproducibility relative standard deviation of 4.9%. The proposed method was compared with reference microbiological and radioisotope protein-binding methods for a range of food samples. A wide selection of milks, infant formulas, meats, and liver were evaluated for their vitamin B12 content. The influence of season was studied in herd milk, early lactation was followed for a single animal, and the cobalamin content of bovine, caprine, and ovine milks was compared.
authors.affiliation: NZMP-Fonterra, Waitoa, New Zealand. harvey.indyk@nzmp.com
authors.forename: Harvey E
authors.initials: HE
authors.lastname: Indyk
authors.forename: Bjorn S
authors.initials: BS
authors.lastname: Persson
authors.forename: Malin C B
authors.initials: MC
authors.lastname: Caselunghe
authors.forename: Anna
authors.initials: A
authors.lastname: Moberg
authors.forename: Enrico L
authors.initials: EL
authors.lastname: Filonzi
authors.forename: David C
authors.initials: DC
authors.lastname: Woollard
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002138:Calibration; D002417:Cattle; D003611:Dairy Products / Q000382:microbiology*; D005260:Female; D005516:Food Microbiology; D006041:Goats; D007202:Indicators and Reagents; D008892:Milk / Q000382:microbiology*; D011485:Protein Binding; D015203:Reproducibility of Results; D012621:Seasons; D012756:Sheep; D014805:Vitamin B 12 / Q000032:analysis*
chemical_list: D007202:Indicators and Reagents; D014805:Vitamin B 12