Controlled-current techniques coulometric measurements

Other techniques for studying protein molecnles in solntion are less infln-enced by these microscopic effects. Square-wave voltammetry is widely used due to its great sensitivity, and even a low density of productive sites on the electrode may give rise to a sharp and analyzable response [28]. The electrode may also be rotated to achieve forced convection and hydrodynamic control of solution redox species, while amperometric (and coulometric) measurements—where the current (or charge) is recorded following a potential step—enable the time and potential domains to be deconvoluted [28,29]. These options complement each other to provide a detailed picture of the thermodynamics and kinetics of redox processes. Finally, bulk electrolytic methods enable samples of a particular redox state to be prepared quantitatively for spectroscopic examination, at precise electrode potentials that may lie outside the range of conventional chemical titrants. 

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