Rudolf Pribil

Present state of complexometry—I: Determination of quadrivalent and tervalent metals

Abstract A review of the visual complexometric determination of quadrivalent and tervalent metals, whether achieved by using new indicators, new titrants, masking agents or new separatory methods, is presented. Attention is paid to the complexometric behaviour of such metals and to the problems of interferences in particular determinations. Older methods, except those which are irreplaceable, are not mentioned.

Extractions with long-chain amines—III: Colorimetric determination of molybdenum as thioglycollate

A highly selective and sensitive colorimetric determination of molybdenum(VI) based on its extraction with a chloroform solution of trioctylamine from solutions of acetic and thioglycollic acid (TGA) is described. The yellow chloroform extract containing the molybdenum-TGA complex is measured at 370 nm. With a single extraction it is possible to determine small amounts of molybdenum in the presence of very large concentrations of almost all metals. Only bismuth, mercury and tungsten interfere.

An electrochemical stripping method for the selective determination of traces of silver

A method has been developed for the determination of traces of silver in the presence of large concentrations of interfering metals, particularly copper, involving reduction of the silver on a glassy-carbon electrode modified by an adsorbed layer of previously deposited hydrogen.