Fig. 3. IR spectra of the nitrogen-tagged disaccharide Galβ(1-4)GlcNAc at 40 K when no ion-mobility separation is applied (top, grey) and after ion-mobility separation and selection of the first (red) and second (blue) drift peak (compare Fig. 2). Adding the spectra of species 1 and 2 in a 4 : 1 ratio yields the synthetic mixture displayed in pink (2nd from top), and subtraction from the conformer unresolved spectrum yields the difference spectrum displayed in grey for comparison.