STUDIES ON SYSTEM PEAKS IN ION-PAIR ADSORPTION CHROMATOGRAPHY .3. REGULATION OF SYSTEM PEAK GRADIENT RETENTION FOR OBTAINING ANALYTE PEAK COMPRESSION

Peak compression can be obtained when an analyte is eluted in the co-ion gradient in a large system peak. Matching of the analyte retention with this gradient was investigated. The chromatographic system was based on silanized silica and an acidic eluent, containing acetonitrile and a probe, which was an UV-detectable hydrophobic amine, protriptyline. Large system peaks, or zones, containing probe deficiencies were induced by injecting high concentrations of a hydrophobic organic anion together with cationic analytes. The back part of these system zones consisted of a steep gradient of increasing probe (co-ion) concentration, giving strongly compressed peaks when low analyte amounts were also eluted with this back-gradient. It was found that variation of the probe concentration was an efficient way of matching the retention of the system peak with analytes of widely varying retentions. © 1990.