Advantages of potentiometric titration

Surfactant-sensitive electrodes are commercially available, and they are also easily made in the laboratory. They can be used to detect the end-point in titrations of anionic and cationic surfactants with surfactants of opposite charge. They are used in exactly the same way as a glass electrode in acid-base titrations, or a silver-silver chloride electrode in titrations of chloride with silver nitrate. The main advantages of potentiometric as opposed to two-phase titration are  

It permits the use of much higher concentrations of titrant (0,02-0.04 M as against 0.004 M), resulting in sharper end-points and thus better reproducibility. 

It eliminates the use of chloroform, whose vapour is toxic and may be carcinogenic. 

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Another advantage of potentiometric titrations is that substances to which the electrode does not respond can be determined, if the electrode responds to the titrant or to some low level of an indicator substance that has been added to the solution. For example, low levels of Al can be determined by titration with standard fluoride solution, using a fluoride electrode [22]. EDTA and other chelates can be determined by titration with standard calcium or copper solution. Manganese(II), vanadium(II), or cobalt(II) can be determined via EDTA titration if a small amount of CuEDTA indicator is added to the solution and a copper electrode is used. The electrode responds directly to the Cu activity which, however, is dependent on the activities of the EDTA and the other metal ion in solution. 

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