Letter: Collision-Induced Dissociation of [Metal(L) 2 ] 2+ Complexes (Metal = Cu,Ca and Mg) of 1-Palmitoyl-2-Oleoyl-sn-Glycero-3-Phosphocholine Allows Distinction of the Acyl Groups at the sn1 and sn2 Positions

Abstract

The collision-induced dissociation (CID) spectra of the divalent metal complexes of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, [Metal^II(L)₂]²⁺ (where Metal = Cu²⁺, Mg²⁺ and Ca²⁺, L = [16:0/18:1GPCho]), formed by electrospray ionization, reveal interesting metal dependent fragmentation chemistry. Six main classes of reaction are observed corresponding to: two competing carboxylate abstraction pathways (from the sn1 and sn2 positions); phosphate abstraction; competing losses of the two different carboxylic acids from the sn1 and sn2 positions; loss of a protonated ligand, [L + H]⁺. The relative ratios of the competing carboxylate abstraction reactions are dependent on the metal, with the Cu and Ca complexes favoring the abstraction of the larger carboxylate (18:1) and the Mg complex favoring the abstraction of the smaller carboxylate (16:0).

Keywords

electrospray ionization tandem mass spectrometry collision induced dissociation diacylgycerophosphocholine

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