Multiwalled carbon nanotubes have been entrapped in monolithic poly(glycidyl methacrylate-. co-ethylene dimethacrylate) capillary columns to afford stationary phases with enhanced liquid chromatographic performance for small molecules in the reversed phase. While the column with no nanotubes exhibited an efficiency of only 1800 plates/m, addition of a small amount of nanotubes to the polymerization mixture increased the efficiency to over 15,000 and 35,000 plates/m at flow rates of 1 and 0.15μL/min, respectively. Alternatively, the native glycidyl methacrylate-based monolith was functionalized with ammonia and, then, shortened carbon nanotubes, bearing carboxyl functionalities, were attached to the pore surface through the aid of electrostatic interactions with the amine functionalities. Reducing the pore size of the monolith enhanced the column efficiency for the retained analyte, benzene, to 30,000 plates/m at a flow rate of 0.25μL/min. Addition of tetrahydrofuran to the typical aqueous acetonitrile eluents improved the peak shape and increased the column efficiency to 44,000 plates/m calculated for the retained benzene peak.
Bibliographical noteFunding Information:
Financial support of S.D.C. and J.M.J.F. by a grant of the National Institute of Health ( GM48364 ) is gratefully acknowledged. All experimental and characterization work performed at the Molecular Foundry, Lawrence Berkeley National Laboratory and F.S. were supported by the Office of Science, Office of Basic Energy Sciences, U.S. Department of Energy, under Contract No. DE-AC02-05CH11231.
- Carbon nanotubes
- Poly(glycidyl methacrylate-co-ethylene dimethacrylate)
- Porous polymer monolith
- Reversed phase chromatography
- Small molecules
ASJC Scopus subject areas
- Analytical Chemistry
- Organic Chemistry