Overview of analytical methods for elemental speciation.
This paper describes a selection of the major developments in the field of analytical methodology for elemental speciation over the period from January 1986 to December 1990. Methods for a number of elements will be highlighted. Judging by the number and diversity of published reports, there has been increasing interest and activity in the development of new and modified analytical methods. Further, it is very encouraging to observe the number of papers concerned with the accuracy and precision of such analytical methods, and with comparisons between two or more methods. Among electrochemical methods of analysis, anodic stripping voltammetry has provided an important basis for measurements of concentrations of labile metals in aqueous media. The fastest growing area of method development is the coupling of separation methods, usually chromatography, with a single- or multi-element detector. Most importantly, inductively coupled plasma mass spectrometry has recently been described as a very sensitive, multi-element detector. The success of a 'coupled' method is greatly dependent on a suitable interface. Several papers have been published recently describing useful interfaces. Chemical extraction procedures continue to occupy an important place. Applications of analytical elemental speciation methods have included environmental, biological, clinical and geological samples. A number of methods for elements most frequently studied will be discussed.