REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF BASIC COMPOUNDS AT PH11 WITH SILICA-BASED COLUMN PACKINGS

These studies describe additional ways in which silica-based column pa ckings can be stabilized for routine use at high pH (pH 9-11). Excelle nt column stability at high pH is obtained by using densely-bonded, en dcapped, longer-chain alkyl column packings with certain organic buffe rs. Column lifetime can be further extended by using untreated silica precolumns that partially saturate the mobile phase entering the analy tical column. Highest stability was obtained with a new densely-bonded , double-endcapped bidentate-C-18 silane stationary phase. Column pack ings with this material exhibit superior stability at pH 11, while mai ntaining the high column efficiency and excellent peak shapes that are characteristic of monofunctional bonded-silane silica-based columns. (C) 1998 Elsevier Science B.V.