Methylation of Residual Carboxyl Groups in Gel Permeation Column and Its Effect on Elution and Distribution of Metals and Proteins in Blood Serum

Abstract

Residual carboxyl groups in gel permeation column materials (hydrophilic polymer gels) (Asahipak GS-520) were methylated with boron trifluoride methanol complex to minimize the interaction of metals between the ligands in substrates and in gel materials. Although zinc ions were eluted very slowly as an extremely broad peak on the original column, the metal ions were eluted faster as a lesser broad peak on the methylated column. Cadmium ions were eluted faster as a relatively sharp peak on the methylated column than the original column. Alkali earth metal ions were eluted also as sharper peaks on the methylated column. Zinc in rat serum was eluted more with globulins and less with albumin on the methylated column than on the original column. Globulins and albumin in rat and human sera were separated more efficiently on the methylated column. These results suggest that methylation of residual carboxyl groups in gel materials decreased the interaction of metals with gel materials and increased hydrophobicity of the gel materials.