Capillary electrophoresis with chemical reaction Effect of ionic strength

Abstract

A brief summary of the results of experimental observations of the effects of electric fields on propagating reaction fronts and pulses is presented. A prototype ionic chemical system consisting of a substrate A⁺ and an autocatalyst B⁺ and two further non-reacting species C^- and D⁺ is then considered when an electric field with a constant current is applied. An autocatalytic reaction between A⁺ and B⁺ with a quadratic rate law is assumed. Results obtained from extensive numerical simulations of the model are reported. These show that the system is capable of supporting a variety of propagating fronts; ‘kinetic waves’, ‘Kohlrausch boundaries’ and complete species separation are all observed as well as a new type of wave front in which there is a much enhanced reaction rate. The behaviour is characterized in terms of the applied electric current, the ionic strength, and the ratio of the diffusion coefficients of the reacting species.

References

1. H. Ševčíková and M. Marek, Physica D, 1983, 9, 140.
2. H. Ševčíková and M. Marek, Physica D, 1984, 13, 379.
3. H. Ševčíková, M. Marek and S. C. Müller, Science, 1992, 257, 951.
4. R. Feeney, S. L. Schmidt and P. Ortoleva, Physica D, 1981, 2, 536.
5. O. Steinbock, J. Schütze and S. C. Müller, Phys. Rev. Lett., 1992, 68, 248.
6. K. I. Agladze and P. De Kepper, J. Phys. Chem., 1992, 96, 5239.
7. A. P. Muñuzuri, M. Gómez-Gesteira, V. Pérez-Muñuzuri, V. I. Krinsky and V. Pérez-Villar, Phys. Rev. E, 1994, 50, 4258.
8. V. eŕrez-Muñuzuri, R. Aliev, B. Vaisev and V. I. Krinsky, Physica D, 1992, 56, 229.
9. S. C. Müller, O. Steinbock and J. Schütze, Physica A, 1995, 188, 47.
10. P. Kaštánek, J. Kosek, D. Šnita, I. Schreiber and M. Marek, Physica D, 1995, 84, 79.
11. H. Ševčíková, J. Kosek and M. Marek, J. Phys. Chem., 1996, 100, 1666.
12. H. Ševčíková, I. Schreiber and M. Marek, J. Phys. Chem., 1996, 100, 19153.
13. D. Šnita and M. Marek, Physica D, 1994, 75, 521.
14. P. Ortoleva, Physica D, 1987, 26, 67.
15. D. Šnita, H. Ševčíková, M. Marek and J. H. Merkin, J. Phys. Chem., 1996, 100, 18740.
16. D. Šnita, H. Ševčíková, M. Marek and J. H. Merkin, Proc. R. Soc. London, Ser. A, 1997, 453, 2325.
17. F. Kohlrausch, Ann. Phys. (Leipzig), 1897, 62, 209.
18. R. A. Mosher, D. A. Saville and W. Thormann, The dynamics of electrophoresis, VCH, Weinheim, 1992.
19. D. Šnita, J. Lindner, M. Marek and J. H. Merkin, Math. Comput. Modell. in press.