Capillary electrochromatography using columns packed with a supercritical fluid carrier

Columns for capillary electrochromatography may be prepared by packing reversed phase silica-based material using a supercritical fluid carbon dioxide carrier. Procedures for the in-situ manufacture of frits and UV detection windows, and the wetting of columns are described. The columns were employed in two commercial instruments (and a home-built system), and their properties investigated during the separation of standard mixtures of test compounds. The columns are highly efficient and durable, with reduced plate heights of 1.0-1.4. The repeatability of retention time, peak area and peak height was measured. The influence of applied voltage, and column temperature and of electrokinetic injection parameters was explored, along with other practical considerations.