[Retention behaviours of neutral solutes in reversed-phase capillary electrochromatography]

In this paper, retention behaviours of neutral solutes in reversed-phase capillary electrochromatography (RP-CEC) was studied separately with methanol, acetonitrile, isopropanol and tetrahydrofuran as organic modifiers. It was found that at certain concentration, the order of mu eo was in accordance with the epsilon/eta value of the organic modifier in the mobile phase. In addition, the relationship between mu eo and phi was relevant to the property of the organic modifier. With more organic modifier in the mobile phase, mu eo increased in methanol-water and acetonitrile-water systems; it changed little in tetrahydrofuran-water system and decreased slightly in isopropanol-water system. Linear relationship between capacity factors of neutral solutes and the volume fraction of the organic modifier in the mobile phase was obtained in CEC, and was similar to that in RP-HPLC. With the same column under the same conditions, it was found that the capacity factors of solutes in RP-CEC and RP-HPLC were almost the same, which means that the retention mechanisms of neutral solutes in these two modes might be quite similar.