Methacrylate-ester-based Reversed Phase Monolithic Columns for High Speed Separation Prepared by Low Temperature UV Photo-polymerization

Butyl methacrylate-based reversed phase capillary monolithic columns were prepared using ultraviolet (UV) photo-polymerization. The effects of two photo-polymerization conditions (UV irradiation intensity and polymerization temperature) on the column characteristics were investigated. Both the higher UV irradiation intensity and the lower polymerization temperature lead to the superior column efficiency. The column prepared under the optimized conditions was evaluated through the separation of the uracil and five alkylbenzenes in the linear flow rate range of 1 - 110 mm/s. At 1 mm/s, all analytes were well separated (N = 36000 - 45000 plates/m). The high speed separation within 8 s was performed at 110 mm/s (back pressure, 33 MPa) at room temperature, whereas the peaks eluted earlier were overlapped partially. The relationship between the flow rate and the back pressure indicated that some kind of structural change of the monolith might occur in 50 - 110 mm/s, although no visible or hysteresis changes of the monolith were observed after the measurement.