EQUILIBRIUM OF OCTADECYLSILICA GEL WITH SODIUM DODECYL-SULFATE

The retention times of tyrosine (Tyr), 3,4-dihydroxyphenylalanine (DOPA), 3,4-dihydroxyphenylethylamine (DA), norepinephrine (NE), epinephrine (E), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxy-4-hydroxymandelic acid (VMA), tryptophan (Trp), 5-hydroxytryptophan (5-HTP), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) on octadecylsilica (ODS) gel gradually changed when the ODS gel column was washed with buffer containing sodium dodecylsulphate (0.003%). To reach the steady state, 3200 column volumes of buffer were required. The retention properties of this column correlated with the hydrophobicity of the retained materials, including Tyr, DOPA, DA, NE, E, HVA, DOPAC, VMA, Trp, 5-HTP, 5-HT and 5-HIAA. These observations are of practical importance in preparing reproducible ODS gel columns for the determination of trace amounts of materials in biological fluids. © 1990.