Accuracy profiles of chemical assays are introduced and derived from the uncertainty of the analytical result. The calculation ..... nine is presented in Table 4. .... [27] D.C. Harris, Quantitative Chemical Analysis, 5th ed., W.H. Freeman, 1999, pp.
Talanta 70 (2006) 896–901
Accuracy profiles from uncertainty measurements ´ A. Gustavo Gonz´alez ∗ , M. Angeles Herrador Department of Analytical Chemistry, University of Seville, Spain Received 19 September 2005; received in revised form 29 December 2005; accepted 8 February 2006 Available online 20 March 2006
1. Introduction The concept of accuracy profile was first introduced in the papers of Hubert et al. [1] and Boulanger et al. [2]. Recently, the commission on the validation of analytical procedures of the Societ´e Franc¸aise des Sciences et Techniques Pharmaceutiques (SFSTP) have used the accuracy profiles for improving the assessment of accuracy in method validation [3–5]. According to the ISO 5725 definition [6], accuracy expresses the closeness or agreement between a test result (Z) and the accepted ˆ which is an estimation of the true unknown reference value (Z), one (µ). Method validation scrutinizes the accuracy of results by considering both systematic and random errors. Accuracy is, therefore studied as an entity with two components: trueness and precision [7,8]. The accuracy of results relates only to the fitness-for-purpose of an analytical system verified by method validation [9]. Instead of assessing trueness and precision independently, it is possible to assess accuracy in a global way according to the concept of acceptability limit λ [3–5]. Thus, the analytical result Z may differ from the estimation of the ˆ in an extent less than the acceptability unknown ‘true value’ Z limit: ˆ
