The Effect of Changes in Collisional Energy on Mass Spectrometric Dissociation Techniques.

Collisonal-induced dissociation (CID) and higher-energy collisional-induced dissociation (HCD) are two common mass spectrometric dissociation techniques used in the generation of MS/MS spectra, which are useful in the elucidation of glycan structures. The two fragmentation techniques are compared via analysis of a glycan coupled with a mass-spectrometric tag. The reagents selectively couple the glycan at its reducing terminus via a reductive amination reaction. For glycan derivatization, 20 µL of 1 mM Lactose in MeOH:H2O (1:1 v/v) is mixed with 30 µL of 20 mM reagent in MeOH. The solvents are removed In Vacuo and the reaction is allowed to take place in a 50 µL reductive amination solution of 50 mM sodium cyanoborohydride (NaBH3CN) in DMSO:GAA (7:3 v/v) for two hours. After which, the solvents are then evaporated In Vacuo and the conjugate is purified via acetone precipitation. Data Acquisition was carried out using a Thermo Scientific™ Q Exactive™ Plus Hybrid Quadrupole-Orbitrap™ mass spectrometer equipped with a heated electrospray ionization (HESI) source for HCD samples. A Thermo Scientific™ Finnigan™ LTQ™ mass spectrometer equipped with an electrospray ionization (ESI) source was used to acquire CID samples. Preliminary data analysis shows that the ratio of peaks produced by the fragmentation of the glycan conjugate under CID does not change with varied collisional energy. This contrasts with HCD, in which the ratio of the peaks can change with varied collisional energy. This suggests that CID and HCD are not identical dissociation techniques; further analysis is needed to show the different information present in each.