ELECTROKINETIC STUDIES OF INORGANIC COATED CAPILLARIES

The procedures for the preparation of silica capillaries coated with t itanium oxide or aluminum oxide are developed. These inorganic coated capillaries are studied for their applicability in capillary electroph oresis. The points of zero charge are measured as pH 5 and pH 7 for ti tanium oxide- and aluminum oxide-coated capillaries, respectively. Bot h titanium oxide and aluminum oxide coatings give better protein separ ations in comparison to the use of fused-silica capillaries. Separatio n efficiency of lysozyme as model protein is measured in the range of 20 000 theoretical plates/m of inorganic coated capillaries. However, the hydrophobic interaction between proteins and modified capillary wa ll possibly contributes to the tailing of observed protein peaks.