| An overview of the development of reversed-phase high-performance liquid chromatography is presented, including a general discussion of the retention behavior of solutes as a function of several mobile phase properties. Emphasis is placed on pH, ionic strength, surface-active ion, and organic modifier effects.; Mixture designs were used to improve the separation of scL-phenylalanine, scL-tyrosine, and scL-tryptophan on a C{dollar}sb{lcub}18{rcub}{dollar} bonded stationary phase. The pH of the mobile phase and retention times of each amino acid were measured for 35 mobile phase formulations containing various concentrations of H{dollar}sb3{dollar}PO{dollar}sb4,{dollar} NaH{dollar}sb2{dollar}PO{dollar}sb4,{dollar} NaClO{dollar}sb4,{dollar} sodium 1-octanesulfonate, and methanol. A nonlinear six-parameter model was used to describe the measured pH as a function of the eluent composition with a standard error of estimate of 0.10 pH units. A different nonlinear ten-parameter model was used to describe the measured retention time as a function of eluent composition for each of the three amino acids with a standard error of estimate of 0.08 min. This last model was then used to predict the composition for which the separation would be optimal. The optimal separation was confirmed experimentally.; The effect of solute concentration and solute charge on the retention behavior of binary samples in high-precision reversed-phase high-performance liquid chromatography was investigated for eight different solute pairs. Plots of retention data for each solute pair suggest an ionic strength effect for early eluting charged solutes, an overload effect for later eluting charged solutes, and neither effect for neutral solutes. |
