946 (2002) 99–106 Journal of Chromatography A, www.elsevier.com / locate / chroma Methacrylate monolithic columns of 320 mm I.D. for capillary liquid chromatography a, a a b a ˇ * ´ ´ ´ ˇ ´ ´ ´ Pavel Coufal , Martin Cihak , Jana Suchankova , Eva Tesarova , Zuzana Bosakova , a ˇ ´ Karel Stulık a Department of Analytical Chemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic b Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic Received 21 September 2001; received in revised form 27 November 2001; accepted 28 November 2001 Abstract Monolithic capillary columns (320 mm I.D.) were prepared for capillary liquid chromatography (CLC) by radical polymerization of butylmethacrylate (BMA) and ethylenedimethacrylate (EDMA) in the presence of a porogen solvent containing propan-1-ol, butane-1,4-diol and water. The influence of the contents of the porogen solvent and EDMA in the polymerization mixture on the monolith porosity and column efficiency was investigated. The composition of the polymerization mixture was optimized to attain a minimum HETP of the order of tens of mm for test compounds with various polarities. The separation performance and selectivity of the most efficient monolithic column prepared was characterized by van Deemter curves, peak asymmetry factors and Walters hydrophobicity and silanol indices. It was demonstrated that the 320-mm I.D. monolithic column exhibited CLC separation performance similar to that observed for 100- and 150-mm I.D. monolithic columns reported in the literature; moreover, the 320-mm I.D. column was easier to operate in CLC and exhibited a higher sample loadability.  2002 Elsevier Science B.V. All rights reserved. Keywords: Monolithic columns; Stationary phases, LC; Methacrylate 1. Introduction I.D. columns in capillary liquid chromatography (CLC) and 10–150 mm I.D. columns in nanoscale Miniaturization of columns in high-performance LC [3]. Miniaturization brings some benefits to the liquid chromatography (HPLC) has been one of the separation process, e.g. decreased amounts of sam- main trends in this separation technique within the ples necessary for injection, small flow-rates of last 10 years [1,2]. Separation columns of the eluents leading to their reduced consumption and a common inner diameters (i.e. 3.2–4.6 mm) used in lowered dilution of analytes in the separation column conventional HPLC have been substituted with 1.5– resulting in an increased sensitivity of detection 3.2 mm I.D. columns in microbore HPLC, 0.5–1.5 [4,5]. mm I.D. columns in microcolumn LC, 150–500 mm Continuous polymer beds (monoliths) were intro- ´ duced by Hjerten et al. in 1989 [6] and subsequently investigated by other research groups [7–9]. Mono- *Corresponding author. E-mail address: pcoufal@natur.cuni.cz (P. Coufal). lithic columns have recently been prepared and 0021-9673 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0021-9673(01)01570-9