Vol. 24, No. 1
from Pure and Applied Chemistry
Analytical Chemistry (IUPAC Recommendations 2001)
Vessman, R.I. Stefan, J.F. van Staden, K. Danzer, W. Lindner, D.T. Burns,
A. Fajgelj, and H. Müller
Pure and Applied Chemistry, Vol. 73, No. 8, pp. 1381-1386 (2001)
is one of the key properties in analytical chemistry.
However, definitions within the framework of IUPAC have been rather
vague. In the analytical chemical community there has also been an unfortunate
overlap between the terms selectivity and specificity,
which has been confusing. As a remedy a project was started in the Analytical
Chemistry Division within IUPAC in 1999, which was finalized in Brisbane
document states that the term selectivity has evolved in parallel
with the development of more sensitive and discriminating methods and
that several kinds of interactions are used in the discrimination process.
in a method is obtained by the combination of several selectivity generating
steps as exemplified by LC-MS-MS (with separation and detection selectivity)
and by arrays of sensors, where computational selectivity is introduced.
can be expressed in a qualitative manner in many ways, but most importantly,
selectivity is something that can be graded in contrast to specificity,
which is absolute. On the other hand, a calculation of degree of selectivity
is not easy and many attempts have been made. A calculation approach
useful to the practicing analyst is therefore still to be desired.
recommendation 2001 states that selectivity should be promoted
and specificity discouraged as the latter is incorrect. A method
is either specific or not, few, if any methods are specific.
From a semantic point of view, the expression that "selectivity
is the state or quality of choosing carefully" has been derived.
definition of Selectivity is: Selectivity refers to the
extent to which the method can be used to determine particular analytes
in mixtures or matrices without interferences from other components
of similar behavior.