Cationic and Anionic Probes

Electrodes are now available for the selective determination of the concentrations of a large number of cations and anions. Halide-sensitive electrodes have been used to monitor reactions, but their relatively slow response has restricted their use. They may have particular utility in the study of reactions with low spectral absorbance changes and also in an ancillary role to the kinetics determination. 

Although the rate of hydrolysis of nitroammine cobalt(III) complexes can be easily measured spectrally, it proved important to monitor for loss of NHj or NOj groups in the early stages by using selective electrodes. The dominant loss of NH3 or NOf in the first stage depended on the complex. 

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