Collision-Induced Dissociation of the Alkali-Metal Adduct Ions [M + c]⁺ and [M + 2c - H]⁺ (c=Na and K): Trolox and a Phospholipid

Abstract

Collision-induced dissociation (CID) spectra of sodium adduct [M + Na]⁺ and [M + 2Na - H]⁺ ions of Trolox and a phospholipid L-α-phosphatidyl-N-monomethylethanolamine, produced under fastatom bombardment conditions, have been compared with the corresponding CID spectra of potassium adduct [M + K]⁺ and [M + 2K - H]⁺ ions, in order to examine the influence of cation size on the CID patterns. While the CID spectra of mono-metal adduct ions [M + c]⁺ (c=Na and K) agreed with each other in pattern, the CID spectrum of dipotassium-adduct [M + 2K - H]⁺ ion of the phospholipid showed a definite pattern of chargeremote fragmentation and it was different from that of di-sodium adduct [M + 2Na - H]⁺ ion in fragment intensity. The CID spectra of di-metal adduct ions [M + 2c - H]⁺ (c=Na and K) gave a number of di-metal containing fragments. On the basis of the results obtained, the structures of alkali metal adduct [M + c]⁺ and [M + 2c - H]⁺ ions have been discussed.