Analysis of complex formation between crown ethers and potassium ion by determining retention factors in reversed-phase high-performance liquid chromatography

Retention factors in reversed-phase high-performance liquid chromatography (RP-HPLC) were utilized for the analysis of complex formation reaction of f our crown ethers with potassium ion in water-methanol media. The crown ethe rs were injected as analytes, potassium ion was present in the eluent, and three types of reversed-phase columns were used. The retention factor of th e crown ethers decreased with increasing concentrations of potassium ion in the eluent, which is attributed to the change in the species of the crown ether from a neutral ligand to a positively charged complex. The complex fo rmation constants were determined by analyzing the changes in the retention factor with a non-linear least-squares method. (C) 2001 Elsevier Science B .V. All rights reserved.