Some interferences in alternating current, differential pulse and other polarographic methods

✍ Scribed by A.M. Bond; B.W. Kelly; G.J. Moloney

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 824 KB
• Volume: 81
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)89455-6

✦ Synopsis

The influence of a preceding electrode process in the analytical use of a.c., differential pulse and other polarographic methods is discussed. Coupled chemical reactions, such as found with the Cr(III)/Fe(III) system, cause considerable interference in all the techniques examined. interference is readily recognized by a shift in peak potential and a change in the wave shape on addition of increasing concentrations of the more positively reduced species. With other systems, a depolarizer more negatively reduced than another can be determined over a wide range of conditions with three-electrode instrumentation. IR-drop problems with two-electrode systems place considerable restrictions on their use. With Zn/Cu and CdlCu and other systems, reliable determinations were possible only when the concentration of the more positively rcduccd species was less than 10-r hl.