Glycan signal enhancement by ammonium fluoride doping and electrospray diverting

By combining ammonium fluoride electrospray doping with an electrospray diverter, signals of N-linked glycans were significantly enhanced. The addition of NH₄F into the electrospray increases signal by deprotonating neutrals and creating [M - H]^- ions. The electrospray diverter can prevent excess background ions from entering the mass spectrometer ion trap, reducing ion suppression. Utilizing these techniques simultaneously resulted in a synergistic effect, increasing signal more than demonstrated previously by either technique. Cleaved N-linked glycans analyzed from a solution showed an average 9-fold signal increase while cleaved N-linked glycans from tissue experienced an average 27-fold increase in signal. These increases showed no statistical differences when considering their m/z, adduct, or specific monosaccharides, suggesting that this technique is highly robust and agnostic to analyte characteristics.