Effect of sample solvent on the chromatographic peak shape of analytes eluted under reversed-phase liquid chromatogaphic conditions.

Peak-shape problems represent the most common troubles in liquid chromatography. Distorted peaks are causes for integration problems, and very often for poor resolutions. Sample and standard solvent different from that of the eluent is one of the possible reasons for anomalous peak-shapes. The injection of a pulse of different viscosity from that of the mobile phase is the underlying cause of distortions in early eluting bands. Strong eluting solvents (of exactly equal viscosity coefficients) are cause of band broadening, not of peak distortions. The goal of the present work is to critically evaluate the significant role of sample solvent upon the chromatographic band distortion. Practical solutions for situations where chromatographic analysis is performed under conditions far from ideal as a result of time constrains related to sample preparation are also discussed.