Organic compounds coulometric analysis

Coulometry may be used for the quantitative analysis of both inorganic and organic compounds. Examples of controlled-potential and controlled-current coulometric methods are discussed in the following sections. 

The second type of cell is a mercury pool type. A mercury cathode is particularly useful for separating easily reduced elements as a preliminary step in an analysis. l or example, copper, nickel, cobalt, silver, and cadmium are readily separated from ions such as aluminum, titanium, the alkali metals, and phosphates. The precipitated elements dissolve in the mercury little hydrogen evolution occurs even at high applied potentials because of large overvoltage effects. A coulomet-ric cell such as that shown in Figure 24-5b is also useful for coulometric determination of metal ions and certain types of organic compounds as well. 

Coulometric bromination is a sensitive, accurate, and convenient method of analysis for unsaturated organic compounds. It is more sensitive and selective than the conventional bromination methods, and, through automation, provides a convenience and saving of time valuable in laboratory use. 

The general course of the anodic oxidation reaction is established by analysis of the reaction products and coulometric measurements. Comparison of the amount of carbon dioxide, which is the final oxidation product from organic compounds, with the number of coulombs passing through the system allows the coulombic efficiency of the electrochemical oxidation process to be evaluated. This quantity may be a function of potential [169], and coulometric measurements are therefore best carried out under potentiostatic conditions. 

Controlled-current coulometry (coulometric titration) can be utilized to determine not-easily oxidizable (or reducible) analytes of different applications via acid-base, precipitation, com-plexation titrations, etc. Furthermore, it benefits short analysis time and small amount determination [2]. Dzudovic et al. [21] reviewed some studies employing acid-base titrations for the determinations of non-aqueous or water-insoluble compounds (organic and inorganic). Typically, acidimetric titrations were undertaken coulometrically based on the EF liberated by the oxidation of the introduced H2O. Coulometric titrations of bases in nonaqueous solvent were performed using anodic depolarizers (titrants) to generate as a source. On the other hand, coulometrically atkalimetric... 

---