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Analytical Chemistry Division (V)


Number: 510/39/98

Title: Selectivity and Specificity in Analytical Chemistry

Task Group
Chairman :
J. Vessman

Members: J.F. van Staden, R.I. Stefan, A. Fajgelj, K. Danzer, W. Lindner, H. Muller, D.T. Burns

Completion Date: 2001 - project completed

To develop an IUPAC recommendation on the proper definition and its use

extract from the Introduction of the provisional recommendations
A very important quality criterion of an analytical method is its capability to deliver signals that are free from interferences and give "true results". The ability to discriminate between the analyte and interfering components has for many years been expressed as the selectivity of a method and measurement system. One clear definition is the following: " Selectivity of a method refers to the extent to which it can determine particular analyte(s) in a complex mixture without interference from other components in the mixture" (1). However, the same meaning has often been given to the term specificity (2). Following earlier concern about the use of these terms (3) IUPAC clarified this overlap by expressing the view that "Specificity is the ultimate of Selectivity" (4). The Compendium of Analytical Nomenclature, Definitive Rules 1997, only mentions these important terms under "related papers" in Chapters 2 and 18 (5). As there is still a tendency to mix up these two terms a discussion clarifying the rationale behind the need to differentiate the use of the terms is given, followed by particular recommendations. [see full text for ref (1) to (5)]

The project was discussed in Berlin (aug 1999) and is in progress. A draft was evaluated by commission V.1 at their 2000 annual meeting in Lisbon and after finalised.

The following recommendations are proposed:

  1. That the term Selectivity be promoted. Selectivity is the recommended term in analytical chemistry to express the extent to which a particular method can determine analytes under given conditions in the presence of interferences from other components in the matrix. Selectivity can be graded. To avoid confusion the use of the term specificity for the same concept is to be discouraged.
  2. Definition of Selectivity. Selectivity of a method refers to the extent to which it can determine particular analytes under given conditions in mixtures or matrices, simple or complex, without interferences from other components.

This project was presented at a poster session at the IUPAC Congress/GA July 2001
>view pdf - 21KB<

A final document is submitted to public review comments until 30 September 2001
> see provisional recommendations

Project completed - IUPAC Recommendations 2001, entitled 'Selectivity in analytical chemistry ' is published in Pure Appl. Chem. 73(8), pp. 1381-1386, 2001.

Last update: 20 November 2001


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