Correlation of Sulphonic Acid Retention Values in RP-IPC with Retention Values in RP-HPLC and Ion Chromatography

Abstract

The logarithm of capacity factor lnk'_ip in reversed-phase ion-pair liquid chromatography (RP-IPC) linearly deceases with methanol concentration (C_b), and the logarithm of capacity factor lnk'_ic in ion-chromatography (IC) linearly decreases with the logarithm of salt concentration (lnC_s). The intercept (Ink^w _ip, A) and slope (c_ip, B) values of a linear relationship between lnk_ip' vs. C_b in RP-IPC and lnk'_ip vs. lnC_s in IC were obtained. The logarithm of capacity factor in RP-HPLC and the logarithm of capacity factor in IC, the solute charges and the parameter B in IC have been selected as the descriptors of solute molecular and electrostatic interaction respectively. It has been observed that the logarithm of capacity factors the parameters lnk and c_ip in RP-IPC can be well correlated with the logaríthm of capacíty factors in RP-HPLC and the logarithm of capacity factors in IC, the solute charges and the parameter B. Both the lnk_RP in RP-HPLC and the lnk_ic in IC, the solute charges and the parameter B made a positive contribution to the retention and the parameter inkj in RP-PC, but made a negative contribution to the parameter c_ip in RP-IPC. It can be concluded that both the molecular and the electrostatic interaction play major role in retention of the ionic solutes in RP-IPC.