title: 4-Chloro-α-cyanocinnamic acid is an efficient soft matrix for cyanocobalamin detection in foodstuffs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS).
abstract: 4-Chloro-α-cyanocinnamic acid (ClCCA) is a very useful matrix able to give the protonated adduct [M+H](+) of intact cyanocobalamin (CNCbl) as the base peak (m/z 1355.58) in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The only fragment observed is [M-CN + H](+•) formed through the facile (•) CN neutral loss reflecting the fairly low Co-C bond energy. All other investigated proton transfer matrices, including α-cyano-4-hydroxycinnamic acid, para-nitroaniline and 2,5-dihydroxybenzoic acid, give rise to a complete decyanation of CNCbl with concomitant formation of [M-CN + H](+•) , [M-CN + Na](+•) and [M-CN + K](+•) adducts at m/z 1329.57, 1351.55 and 1367.51, respectively. Depending on the matrix used, a variable degree of fragmentation involving the α-side axial ligand was observed. A plausible explanation of the specific behaviour of 4-chloro-α-cyanocinnamic acid as a soft matrix is discussed. Tandem mass spectra of both [M + H](+) and [M-CN + H](+•) ions were obtained and product ions successfully assigned. The possibility of detecting the protonated adduct of intact CNCbl was exploited in foodstuff samples such as cow milk and hen egg yolk by MALDI tandem MS upon sample extraction. We believe that our data provide strong basis for the application of MALDI tandem MS in the qualitative analysis of natural CNCbl, including fish, liver and meat samples. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.|Centro di Ricerca Interdipartimentale S.M.A.R.T, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.
authors.forename: Cosima Damiana
authors.initials: CD
authors.lastname: Calvano
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ventura
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.|Centro di Ricerca Interdipartimentale S.M.A.R.T, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Palmisano
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.|Centro di Ricerca Interdipartimentale S.M.A.R.T, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona, 4, 70126, Bari, Italy.
authors.forename: Tommaso R I
authors.initials: TR
authors.lastname: Cataldi
mesh_terms: D000818:Animals; D002934:Cinnamates / Q000737:chemistry*; D003611:Dairy Products / Q000032:analysis; D048388:Gadiformes; D008099:Liver / Q000737:chemistry; D008460:Meat / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014805:Vitamin B 12 / Q000032:analysis*
chemical_list: C532442:4-chloro-alpha-cyanocinnamic acid; D002934:Cinnamates; D014805:Vitamin B 12
keywords: MALDI; cyanocobalamin; protonating matrix; tandem MS; vitamin B12