PEAK DISTORTION IN REVERSED-PHASE LIQUID-CHROMATOGRAPHY AS A CONSEQUENCE OF VISCOSITY DIFFERENCES BETWEEN SAMPLE SOLVENT AND MOBILE-PHASE

Solute peaks may suffer severe distortions when their solutions in sol vents whose viscosities differ from those of the mobile phase are inje cted in typical RPLC columns. A series of experiments with carefully c hosen systems were performed, employing octyl silica columns, sample s olvents whose viscosities were higher or lower than those of the corre sponding mobile phases, and solutes that were more or less retained th en the corresponding sample solvents. For a given viscosity difference , the importance of the distortions increases as the difference betwee n solute and sample solvent retention times decreases. Chromatographic systems can be classified into four categories, and chromatograms ill ustrative of all of them were obtained. (C) 1998 Elsevier Science B.V.