Abstract
Ion-selective electrodes (ISEs), apart from fluoride, calcium, and a few others, have not often been used to obtain thermodynamic information on electrolytes. Here, novel cyclodextrin-based ISEs are used to determine activity coefficients of some onium chlorides in aqueous solution. Cyclodextrins, rendered lipophilic by alkylation, have been incorporated into polymeric membranes and used as ionophores in ISEs for sensing the substituted ammonium (onium) ions, choline, acetylcholine, and acetyl-β-methylcholine. Potentiometric measurements using these cyclodextrin-based ISEs allow the determination of ratios of activity coefficients in solutions. Choosing one solution as reference and using a theoretical model (e.g., Pitzer equations), it is possible to evaluate activity coefficients of individual solutions. Results for choline chloride compare well with limited data in the literature. This is the first time, that ISEs have been used to measure activity coefficients of biologically important ions.
Similar content being viewed by others
REFERENCES
D. Parker, R. Kataky, P. M. Kelly, and S. Palmer, Pure Appl. Chem. 68, 1219 (1996); R. Kataky, D. Parker, and P. M. Kelly, Scand J. Clin. Lab. Invest. 35, 409 (1995).
P. M. Kelly, R. Kataky, D. Parker, and A. F. Patty, J. Chem Soc. Perkin II, p. 1955 (1995).
A. Craggs, G. J. Moody, and J. D. R. Thomas, J. Chem. Edu. 51, 541 (1974).
R. G. Bates, Determination of pH: Theory and Practice, 2nd edn. (Wiley-Interscience, New York, 1973).
E. A. Guggenheim and J. C. Turgeon, Trans. Faraday Soc. 51, 747 (1955).
R. A. Robinson and R. H. Stokes, Electrolyte Solutions (Butterworths, London, 1959).
K. S. Pitzer, Activity Coefficients in Electrolyte Solutions, 2nd edn. (CRC Press, Boca Raton, FL, 1991).
G. E. Boyd, A. Schwarz, and S. Lindenbaum, J. Phys. Chem. 70, 821 (1966).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Barriada, J.L., Covington, A.K. & Kataky, R. New Cyclodextrin-Based Ion-Selective Electrodes for Determining Activity Coefficients of Biologically Important Onium Ions. Journal of Solution Chemistry 28, 555–565 (1999). https://doi.org/10.1023/A:1022682915813
Issue Date:
DOI: https://doi.org/10.1023/A:1022682915813