Dynamics of Water/Methanol
Mixtures at Functionalized
Chromatographic Interfaces
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Abstract
Fully atomistic simulations of water/methanol mixtures
of varying
compositions (80/20 and 50/50) at chromatographic interfaces with
different functionalizations are presented. The dynamical properties
in terms of equilibration times and solvent exchange dynamics are
characterized and found to depend on the different systems on the
nanosecond time scale. The solvent density profile and the structuring
of the stationary phase differ for derivatizations including (−CN,
NO<sub>2</sub>, −NH<sub>2</sub>, −C<sub>6</sub>H<sub>5</sub>) of the C<sub>18</sub> chain. The time scale and intensity
of the water exchange dynamics differs for the different realizations
of the chromatographic systems and ranges from 200 to 500 ps. Water
exchange rates depend on solvent composition as well as on the functionalization
of alkyl chains. Simulations with acridine as a probe molecule provide
atomistic insight into the slot model