Technique, electrochemical coulometric titration

Such an electrochemical arrangement can also be used to transport oxygen from one electrode to the other by the imposition of an externally applied potential. This technique, known as coulometric titration , has been used to prepare flowing gas mixtures of oxygen/argon with a controlled oxygen partial pressure, to vary the non-stoichiometry of oxides, to study the thermodynamics of dilute oxygen solutions in metals, and to measure the kinetics of metal oxidation, as examples. 

Coulometers, like the balance, are basic instruments for absolute analysis and they are still used as the most reliable and precise instruments for the analysis of absolute standards. Coulometers are frequently used in elucidating electrochemical reactions because they allow determining the number of transferred electrons when the molar amount of electrolyzed compound is known (-> Faraday s law). When the charge is measured as a function of time, the technique is called chrono-coulometry. See also coulometric titration. 

Both techniques take place within an electrochemical cell. A coulometric titrator equipped with a working electrode of large surface area and an auxiliary electrode separated from the reaction compartment by a diaphragm. This protection of the second electrode provides a barrier between the species formed in contact with it and those formed at the working electrode thus avoiding an eventual reaction (see Figure 20.14). 

As charge is inserted or removed at low rates, the polymer film behaves as a (redox) capacitor. The redox capacity of electroactive films is a quantity of fundamental importance, and it may be determined by several complementary techniques including cyclic voltammetry, electrochemical impedance and coulometric titration. Cyclic voltammetry of a redox polymer film at a slow... 

Emf measurements Transiem technique combined with coulomelric titration Transiem experiments with coulomelric titration Transiem experiments with coulometric titration Electrochemical formation... 

With coulometric Karl Fischer titrations, the iodine is generated electrochemically at the anode. This is a much more accurate technique for measuring water content in a sample. Sample sizes are much smaller compared with those for volumetric Karl Fischer titrations. 

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