Reduction of reequilibration time following gradient elution reversed-phase liquid chromatography

A simple and convenient method for the reduction of column reequilibration time following gradient elution reversed-phase liquid chromatography is described. This method utilizes the addition of a constant volume of 3% 1-propanol to the mobile phase throughout the solvent gradient to provide consistent solvation of the reversed-phase stationary phase. Reductions in reequilibration time of up to 78% have been observed. The effect of alkyl chain bonding density on reequilibration volume is also examined. A maximum in the mobile phase volume necessary to reequilibrate the column is found at a bonding density of about 2.9 mumol/m2. The relationship of reequilibration volume to bonding density supports the partitioning model of retention for reversed-phase liquid chromatography.