The more intense elongation in the positive peak for Gal3C-PEG 5 kDa implies that the long PEG chain would induce more significant conformational flexibility and/or solvent interaction compared to the small PEG chain. Additionally, at short waiting time (t2) such as 150 fs (Figure , left), the peak is diagonally elongated, indicating strong correlation between excitation and detection frequencies. This correlation is lost at longer t2 due to the effects mentioned above (Figure , right, Figures ).