Effects of large volume injection of aliphatic alcohols as sample diluents on the retention of low hydrophobic solutes in reversed-phase liquid chromatography

Recent studies showed that injection of large volume of hydrophobic solvents used as sample diluents
could be applied in reversed-phase liquid chromatography (RP-LC). This study reports a systematic
research focused on the influence of a series of aliphatic alcohols (from methanol to 1-octanol) on the
retention process in RP-LC, when large volumes of sample are injected on the column. Several model
analytes with low hydrophobic character were studied by RP-LC process, for mobile phases containing
methanol or acetonitrile as organic modifiers in different proportions with aqueous component. It was
found that starting with 1-butanol, the aliphatic alcohols can be used as sample solvents and they can
be injected in high volumes, but they may influence the retention factor and peak shape of the dissolved
solutes. The dependence of the retention factor of the studied analytes on the injection volume of these
alcohols is linear, with a decrease of its value as the sample volume is increased. The retention process in
case of injecting up to 200 L of upper alcohols is dependent also on the content of the organic modifier
(methanol or acetonitrile) in mobile phase.