1. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.1 A typical Clark cell, an amperometric oxygen sensor employing a working cathode of platinum and an Ag | AgCl reference anode. A thin film of solution occupies the space between the WE and the membrane. The oxygen in external contact with the membrane may be in a gaseous or an aqueous phase.

2. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.2 The four reactions utilized by the electrochemical glucose sensor

3. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.3 Electrode potential and current traces during stripping voltammetry.

4. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.4 In the standardization procedure, several samples of known concentration are determined in exactly the same way as is the unknown sample. The “best straight line” is drawn by eye through the known points on a graph of signal versus concentration (or a “least squares” analysis is performed numerically - see Web#653). The sought concentration is then found by the interpolation procedure indicated by the blue arrows.

5. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.5 In the standard addition procedure, the sample of unknown concentration is first determined. Then a small known amount of the analyte is added and the determination is repeated. Several more additions are made. After each addition, the “added concentration” is calculated, and a best-straight-line graph is made, as shown. The sought concentration is then found from the “negative intercept” as the diagram indicates.

6. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.6 In a combined process, the colloidal aluminum hydroxide particles produced from dissolving aluminum anodes adsorb pollutants and are buoyed by the hydrogen bubbles produced at the inert cathodes. During its tortuous path through the cell, the water loses many of its contaminants..

7. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.7 One design of an electrochemical ozone-generation cell.

8. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.8 The “twin-tailed tadpoles” represent phospholipid molecules forming a bilayer, here shown in cross section, separating the exterior and interior of a biological cell. The diagram illustrates two ways in which specific ions may transit the bilayer. Ions can shuttle back and forth within an ionophore carrier or stream through a transmembrane channel. The molecules that confer ion permeability adopt hollow sphere or hollow cylinder shapes and have hydrophillic and lipophillic regions, as do the phospholipid molecules themselves.

9. Electrochemical Science and Technology: Fundamentals and Applications, Keith B. Oldham, Jan C. Myland and Alan M. Bond. © 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd. Figure 9.9 Schematic diagram of neuron morphology.