A.J. Bard, L.R. Faulkner - Electrochemical methods - Fundamentals and Applications (794273), страница 24
Текст из файла (страница 24)
Ingeneral, such a device involves a glass pH electrode that is protected from the test solution by a polymer diaphragm. Between the glass membrane and the diaphragm is a smallvolume of electrolyte. Small molecules, such as SO2, NH3, and CO2, can penetrate themembrane and interact with the trapped electrolyte by reactions that produce changes inpH.
The glass electrode responds to the alterations in acidity.Electrochemical cells that use a solid electrolyte composed of zirconium dioxide containing Y2O3 (yttria-stabilized zirconia) are available to measure the oxygen content ofgases at high temperature. In fact, sensors of this type are widely used to monitor the exhaust gas from the internal combustion engines of motor vehicles, so that the airto-fuel mixture can be controlled to minimize the emission of pollutants such as CO andNOX. This solid electrolyte shows good conductivity only at high temperatures(500-1,000°C), where the conduction process is the migration of oxide ions.
A typicalsensor is composed of a tube of zirconia with Pt electrodes deposited on the inside andoutside of the tube. The outside electrode contacts air with a known partial pressure ofOuter bodyInner bodyO-ringSpacer— Bottom capSensing elementMembraneFigure 2.4.5 Structure of a gas-sensingelectrode. [Courtesy of Orion Research, Inc/82Chapter 2. Potentials and Thermodynamics of Cellsoxygen, p a , and serves as the reference electrode.
The inside of the tube is exposed to thehot exhaust gas with a lower oxygen partial pressure, p e g . The cell configuration can thusbe writtenPt/O2 (exhaust gas, peg)/Zr02+ Y 2 O 3 /O 2 (air,/?a)/Pt(2.4.21)and the potential of this oxygen concentration cell can be used to measure pQg (Problem2.19).We note here that the widely employed Clark oxygen electrode differs fundamentallyfrom these devices (18, 63). The Clark device is similar in construction to the apparatus ofFigure 2.4.5, in that a polymer membrane traps an electrolyte against a sensing surface.However, the sensor is a platinum electrode, and the analytical signal is the steady-statecurrent flow due to the faradaic reduction of molecular oxygen.2.4.5Enzyme-Coupled DevicesThe natural specificity of enzyme-catalyzed reactions can be used as the basis for selective detection of analytes (49, 64-68). One fruitful approach has featured potentiometricsensors with a structure similar to that of Figure 2.4.5, with the difference that the gap between the ion-selective electrode and the polymer diaphragm is filled with a matrix inwhich an enzyme is immobilized.For example, urease, together with a buffered electrolyte, might be held in a crosslinked polyacrylamide gel.
When the electrode is immersed in a test solution, there will bea selective response toward urea, which diffuses through the diaphragm into the gel. Theresponse comes about because the urease catalyzes the process:ОN H 2 — С—NH 2 + H + + 2H 2 OUreaseнсо;(2.4.22)The resulting ammonium ions can be detected with a cation-sensitive glass membrane.Alternatively, one could use a gas-sensing electrode for ammonia in place of the glasselectrode, so that interferences from H + , Na + , and K + are reduced.The research literature features many examples of this basic strategy.
Different enzymes allow selective determinations of single species, such as glucose (with glucose oxidase), or groups of substances such as the L-amino acids (with L-amino acid oxidase).Recent reviews should be consulted for a more complete view of the field (66-68).Amperometric enzyme electrodes are discussed in Sections 14.2.5 and 14.4.2(c).2.5 REFERENCES1.
The arguments presented here follow thosegiven earlier by D. A. Maclnnes ("The Principles of Electrochemistry," Dover, New York,1961, pp. 110-113) and by J. J. Lingane("Electroanalytical Chemistry," 2nd ed., Wiley Interscience, New York, 1958, pp. 40-45).Experiments like those described here were actually carried out by H. Jahn (Z.
Physik. С hem.,18, 399 (1895).2. I. M. Klotz and R. M. Rosenberg, "ChemicalThermodynamics," 4th ed., Benjamin/Cummings, Menlo Park, CA, 1986.3. J. J. Lingane, "Electroanalytical Chemistry," 2nded., Wiley-Interscience, New York, 1958, Chap. 3.4. F. C. Anson, /. Chem.
Educ., 36, 394 (1959).5. A. J. Bard, R. Parsons, and J. Jordan, Eds.,"Standard Potentials in Aqueous Solutions,"Marcel Dekker, New York, 1985.6. http://webbook.nist.gov/, National Institute ofStandards and Technology.7. A. J. Bard and H. Lund, Eds., "Encyclopedia ofElectrochemistry of the Elements," MarcelDekker, New York, 1973-1980.2.5 References8. M. W. Chase, Jr., "NIST-JANAF Thermochemical Tables," 4th ed., American Chemical Society, Washington, and American Institute ofPhysics, New York, for the National Institute ofStandards and Technology, 1998.9. L.
R. Faulkner, /. Chem. Educ, 60, 262 (1983).10. R. Parsons in A. J. Bard, R. Parsons, and J. Jordan, Eds., op.cit., Chap. 1.11. A. Henglein, Ber. Bunsenges. Phys. Chem., 94,600 (1990).12. A. Henglein, Top. Curr. Chem., 1988, 113.13. A. Henglein, Accts. Chem. Res., 9, 1861 (1989).14. D. W.
Suggs and A. J. Bard, /. Am. Chem. Soc,116, 10725 (1994).15. R. Parsons, op. cit., p. 5.16. D. J. G. Ives and G. J. Janz, Eds., "ReferenceElectrodes," Academic, New York, 1961.17. J. N. Butler, Adv. Electrochem. Electrochem.Engr.,7, 77 (1970).8332. D. A. Maclnnes, op. cit., Chap. 4.33. /Ш.,Спар. 18.34. D. O. Raleigh, Electroanal. Chem., 6, 87 (1973).35. G. Holzapfel, "Solid State Electrochemistry" inEncycl. Phys.
Sci. TechnoL, R. A. Meyers, Ed.,Academic, New York, 1992, Vol. 15, p. 471.36. J. O'M. Bockris and A. K. N. Reddy, op. cit.,Chap. 3.37. R. G. Bates, "Determination of pH," 2nd ed.,Wiley-Interscience, New York, 1973.38. R. M. Garrels in "Glass Electrodes for Hydrogenand Other Cations," G. Eisenman, Ed., MarcelDekker, New York, 1967, Chap. 13.39. P. R. Mussini, S. Rondinini, A.
Cipolli, R. Manenti and M. Mauretti, Ber. Bunsenges. Phys.Chem., 97, 1034(1993).40. H. H. J. Girault and D. J. Schiffrin, Electroanal.Chem., 15, 1 (1989).41. H. H. J. Girault, Mod. Asp. Electrochem., 25, 1(1993).18. D. T. Sawyer, A. Sobkowiak, and J. L. Roberts,Jr., "Electrochemistry for Chemists," 2nd ed.,Wiley, New York, 1995.42. P. Vany sek, "Electrochemistry on Liquid/LiquidInterfaces," Springer, Berlin, 1985.19. G.
Gritzner and J. Kuta, Pure Appl. Chem., 56,461 (1984).43. A. G. Volkov and D. W. Deamer, Eds., "LiquidLiquid Interfaces," CRC, Boca Raton, FL, 1996.20. (a) P. Peerce and A. J. Bard, /. ElectroanalChem., 108, 121 (1980); (b) R. M. Kannuck, J.M. Bellama, E. A Blubaugh, and R. A. Durst,Anal. Chem., 59, 1473 (1987).44. A.
G. Volkov, D. W. Deamer, D. L. Tanelian, andV. S Markin, "Liquid Interfaces in Chemistry andBiology," Wiley-Interscience, New York, 1997.21. D. Halliday and R. Resnick, "Physics," 3rd ed.,Wiley, New York, 1978, Chap. 29.22. Ibid., Chap. 28.23. J. O'M. Bockris and A. K. N. Reddy, "ModernElectrochemistry," Vol. 2, Plenum, New York,1970, Chap. 7.24. K.
J. Vetter, "Electrochemical Kinetics," Academic, New York, 1967.25. В. Е. Conway, "Theory and Principles of Electrode Processes," Ronald, New York, 1965,Chap. 13.26. R. Parsons, Mod. Asp. Electrochem., 1, 103(1954).27. J. A. V. Butler, Proc. Roy. Soc, London, 112A,129 (1926).28. E. A. Guggenheim, /. Phys. Chem., 33, 842(1929); 34, 1540 (1930).29. S. Trasatti, Pure Appl. Chem., 58, 955 (1986).45. E. Grunwald, G. Baughman, and G.
Kohnstam,/. Am. Chem. Soc, 82, 5801 (1960).46. M. Dole, "The Glass Electrode," Wiley, NewYork, 1941.47. G. Eisenman, Ed., "Glass Electrodes for Hydrogen and Other Cations," Marcel Dekker, NewYork, 1967.48. R. A. Durst, Ed., "Ion Selective Electrodes,"Nat. Bur. Stand. Spec. Pub. 314, U.S. Government Printing Office, Washington, 1969.49. N. Lakshminarayanaiah in "Electrochemistry,"(A Specialist Periodical Report), Vols. 2, 4, 5,and 7; G. J. Hills (Vol. 2); and H. R. Thirsk(Vols, 4, 5, and 7); Senior Reporters, ChemicalSociety, London, 1972, 1974, 1975, and 1980.50. H. Freiser, "Ion-Selective Electrodes in Analytical Chemistry," Plenum, New York, Vol. 1,1979; Vol.
2, 1980.30. D. A. Maclnnes, "Principles of Electrochemistry," Dover, New York, 1961, Chap. 13.51. J. Koryta and K. Stulik, 'Ion-Selective Electrodes," 2nd ed., Cambridge University Press,Cambridge, 1983.31. J. O'M. Bockris and A. K. N. Reddy, op. cit.,Vol. 1, Chap. 4.52.
A. Evans, "Potentiometry and Ion SelectiveElectrodes," Wiley, New York, 1987.84 Э Chapter 2. Potentials and Thermodynamics of Cells53. D. Ammann, "Ion-Selective Microelectrodes:Principles, Design, and Application," Springer,Berlin, 1986.54. E. Lindner, K. Toth, and E. Pungor, "DynamicCharacteristics of Ion-Sensitive Electrodes,"CRC, Boca Raton, FL, 1988.61. T. Sokalski, A. Ceresa, T. Zwicki, and E.Pretsch, /. Am. Chem. Soc, 119, 11347 (1997).62.
J. W. Ross, J. H. Riseman, and J. A. Krueger,Pure Appi Chem., 36, 473 (1973).63. L. С Clark, Jr., Trans. Am. Soc. Artif. Intern.Organs, 2, 41 (1956).55. Y. Umezawa, Ed., "CRC Handbook of Ion-Selective Electrodes," CRC, Boca Raton, FL 1990.64. G. G. Guilbault, Pure Appl. Chem., 25, 727(1971).56. E. Bakker, P. Buhlmann, and E. Pretsch, Chem.Rev., 97, 3083 (1997).65. G.
A. Rechnitz, Chem. Engr. News, 53 (4), 29{1915).57. P. Buhlmann, E. Pretsch, and E. Bakker, Chem.Rev., 98, 1593 (1998).66. E. A. H. Hall, "Biosensors," Prentice Hall, Englewood Cliffs, NJ, 1991, Chap. 9.58. R. P. Buck and E. Lindner, Accts. Chem. Res.,31, 257 (1998).59. E. Pungor, Pure Appl. Chem., 64, 503 (1992).60.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
