Conductometry practice

As we shall see, the solution conductivity depends on the ion concentration and the characteristic mobility of the ions present. Therefore, conductivity measurements of simple, one-solute solutions can be interpreted to indicate the concentration of ions (as in the determination of solubility or the degree of dissociation) or the mobility of ions (as in the investigations of the degree of solvation, complexation, or association of ions). In multiple-solute solutions, the contribution of a single ionic solute to the total solution conductivity cannot be determined by conductance measurements alone. This lack of specificity or selectivity of the conductance parameter combined with the degree of tedium usually associated with electrolytic conductivity measurements has, in the past, discouraged the development of conductometry as a widespread electroanalyti-cal technique. Today, there is a substantial reawakening of interest in the practical applications of conductometry. Recent electronic developments have resulted in automated precision conductometric instrumentation and applications... 

The third category of salinity methodologies was based on conductometry, as the conductivity of a solution is proportional to the total salt content. Standard Seawater, now also certified with respect to conductivity, provides the appropriate calibrant solution. The conductivity of a sample is measured relative to the standard and converted to salinity in practical salinity units (psu). Note that although psu has replaced the outmoded %o, usually units are ignored altogether in modern usage. These techniques continue to be the most widely used methods because conductivity measurements can provide salinity values with a precision of 0.001 psu. Highly precise determinations require temperature control of samples and standards to within 0.001 °C. Application of a non-specific technique like conductometry relies upon the assumption that the sea-salt... 

Loveland JW (1963) Conductometry and Oscillometry. In KolthofFiM, Living PJ and Sandell LB, eds. Treatise on analytical chemistry. Part I (Theory and practice), Vol 4, section D-2, Electrical methods of analysis (Reilley CN, section advisor), pp. 2569-2630. John Wiley Sons, New York. 

Practically all commonly employed electroanalytical methods can be used in environmental analysis the choice of method depends on the character of the compound to be determined and of the matrix in which it occurs, as well as on sensitivity and selectivity requirements. The principal methods are voltammetry and polarography, potentiometry, coulo-metry and conductometry. 

In the preceding chapter the different products/materials, in which alpha acids have to be determined, were mentioned. Undoubtedly hops, hop pellets and hop extracts are the most important. Analysis of alpha acids in wort and beer may also be worthwhile. Of all the possible methods to quantify alpha acids in these products, conductometry and reversed phase liquid chromatography are, at the present time, the only practical possibilities. In this Chapter these methods will be discussed in more detail. 

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