Method for Dead Time Determination in Reversed-Phase Capillary Electrochromatography with Methacrylate-Based Stationary Phases

A method for dead time determination in reversed-phase capillary electrochromatography (RP-CEC) with methacrylate-based monolithic stationary phases has been presented based on homologue series method. The dead times measured with homologue series method and thiourea, a commonly used electroosmotic flow (EOF) marker are compared under various conditions, such as the type and the concentration of organic modifier, ionic strength, and applied voltage. Results show that the former one is larger than the latter one. Under high ionic strength and low applied voltage, EOF velocity measured by thiourea is close to that determined by homologue series method.