Anal. Chem. 1989, 61, 2391-2394
ACKNOWLEDGMENT The authors thank Ms. Eriberta N. Navera for help in compling this paper.
LITERATURE CITED (1) Kada, T.; Turikawa, K.; Sadaie. Y., Mutat. Res. 1972, 16, 165-174. (2) A M s , B. N.; Lee, F. D.; Durston, W. E., R o c . Natl. Acad. Sci. U . S . A . 1973, 70, 782-786. (3) Ames, 6. N., Durston, W. E.; Yamasaki, E.; Lee, F. D.; R o c . Natl. A-d. Scl. U . S . A . 1973, 70, 2281-2285. (4) Bridges, B. A.; Mottershead, R. P.; Rothweii, M. A,; Green, M. H. L. Chem.-Bid. Interact. 1972, 5 , 77-84. (5) Uiltzur, S.; Weiser, 1.; Yannai, S. Mutat. Res. 1960, 74, 113-124. (6) Uiltzur, S.; Weiser, 1.; Yannai, S. Mutat. Res. 1961, 91, 443-450.
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(7) Turner, A. P. F.; Karube, I.; Wiiison, G. S. Biosensors-Fundamentals and Applications; Oxford University Press: Oxford, 1987. (8) Karube, I.; Nakahara, T.; Matsunaga, T.; Suzuki, S. Anal. Chem. 1962, 54, 1725-1727. (9) Karube, I.; Nakahara, T.; Matsunaga, T.; Suzuki, S. Anal. Chem. 1961, 5 3 , 1024-1026. (10) Moreau, P.; Bailone, A.; Devoret, R. R o c . Natl. Acad. Sci. U . S . A . 1978, 73, 3700-3704. (11) Ikeda, H. Hen-igen to Dokusei 1979, 8 , 48-54. (12) Suzuki, S.; Tamiya, E.; Karube, I . Anal. Chem. 1968, 6 0 , 1078-1080.
RECEIVED for review November 14, 1988. Accepted August 17, 1989.
Characterization of Conducting Polymeric Stationary Phases and Electrochemically Controlled High-Performance Liquid Chromatography Hailin Ge and G. G. Wallace* Chemistry Department, Uniuersity of Wollongong, P.O. Box 1144, Wollongong, New South Wales 2500, Australia
A conductive polymer, polypyrroie containing dodecyi sulfate as counterlon, was electrosyntheslred on retkuiated vitreous carbon particles. The particles were packed into a column and the chromatographic performance of this new statlonary phase was evaluated. The use of potential control to Influence the Chromatographic behavior was investigated in a specially designed column. Mixed mode chromatographic behavlor was ldenwled during these experiments. Separation of the isomers m-toluic acid and p-toluic acid, as well as dimethyl phtaiate and dlethyi phthalate, indicates that useful seiecrtlvity can be obtained In this new stationary phase.
In previous work (1) carried out in these laboratories, the concept of using conducting polymers as chromatographic stationary phases was introduced. The use of conducting polymers enablea a convenient stationary phase synthesis route to be devised and also allows for electrochemical control of the stationary phase using an appropriately designed column. Conducting polymers may be synthesized either chemically or electrochemically according to
A number of polymers such as polypyrrole, polyaniline, polythiophene, polyfuran, as well as various derivatives can be produced in this way using either chemical or electrochemical oxidation ( 2 ) . Further flexibility in the design and synthesis of the stationary phase is available in that a range of counterions can be incorporated into these conducting polymers (2-8). Consequently, the mode of chromatography can be modified by employing appropriate monomers and counterions. An additional feature which makes the use of conducting polymers as chromatographic stationary phases attractive is the fact that the polymer properties can be altered electrochemically. For example, by switching the polymer from the conducting to less conducting state either chemically or 0003-2700/89/0361-2391$01.50/0
electrochemically,then counterions can be released from the polymer according to (2, 4-11)
This process also converts the polymer from a charged conductive state to a noncharged less conductive state. In the course of this work, new procedures for preparing conducting polymer chromatographic stationary phases have been developed. This procedure can be used to coat either conductive or nonconductive particles. A polypy-rroldodecyl sulfate polymer has been prepared and the chromatographic properties investigated and compared with commercially available columns. A new electrochemically controlled column has also been produced and employed to study the effects of the applied potential on this new stationary phase. Electrochromatographyhas been employed previously (12), however mostly using only carbon based particles. Some workers (13,14) have investigated the possibility of attaching modifiers to the carbon-based materials to modify chromatographic selectivity. The use of conducting polymers allows the properties of the stationary phase to be altered more markedly with electrochromatography.
EXPERIMENTAL SECTION Reagents and Materials. All reagents were analytical reagent (AR) grade unless otherwise stated. Pyrrole (Fluka, LR grade) was distilled before used. The solution employed in the electrochemical polymerization procedure was 0.2 M pyrrole and 0.1 M sodium dodecyl sulfate (SDS) in water. Dimethyl phthalate, diethyl phthalate, naphthalene, anthracene, benzoic acid, and m-toluic acid were 30 ppm while theophylline and caffeine were 10 ppm. All samples for injection were prepared in the mobile phase. Reticulated vitreous carbon (RVC) obtained from Energy Research Generation, Inc., was crushed to
