Different electrospray tandem mass spectrometric approaches for rapid characterization of phospholipid classes of Curosurf, a natural pulmonary surfactant.

Curosurf is a pulmonary surfactant used in the treatment or prophylaxis of neonatal respiratory distress syndrome. It contains low molecular weight hydrophobic apoproteins and a series of lipids including phosphatidylcholines, lisophosphatidylcholines, phosphatidylethanolamines, sphingomyelins, phosphatidylinositols, phosphatidylglycerols and phosphatidylserines. In the present work, a rapid method to qualitatively map the Curosurf phospholipid classes without prior derivatization or chromatographic separations is described. In particular, a series of specific electrospray tandem mass spectrometric (ES-MS/MS) experiments, i.e. product ion, precursor ion and neutral loss scans, were chosen on the basis of the chemical nature of each phospholipid class and then used to identify single components of the commercial suspension, directly infused into the ion source of the mass spectrometer.

On the detailed mechanisms of collision-induced dissociation experiments performed by electrospray ion trap.

The product ion spectra obtained by electrospray ionization (ESI) ion trap instruments exhibit a higher number of fragment ions than those achieved by other ion-trap-based systems, indicating the presence of more effective energy deposition mechanisms. This behavior can be attributed to several different reasons, among which different initial internal energy of the precursor ions, pre-activation due to collisions taking place outside the trap, different target gas mixtures inside the trap, and different ion trap geometry were considered. Data obtained from experiments using a triple quadrupole instrument, CI-ion trap, and ESI-ion trap have been compared. The results so achieved seem to indicate that the presence inside the trap of neutral molecules of the solvent employed for the ESI process have a relevant role, promoting high energy deposition in the colliding ions.