title: Estimation of the uncertainty associated with the standard addition methodology when a matrix effect is detected.
abstract: If a matrix effect is detected during the validation stage of an analytical method, the standard addition methodology must be applied. To reach a good estimation of the uncertainty associated with the determination, an adequate identification and evaluation of each uncertainty source should be done. As an example to illustrate how to calculate the uncertainty in this case, the simultaneous determination of V(V) and Mo(VI) at trace levels after precolumn chelation and extraction with N-benzoyl-N-phenylhydroxylamine, has been selected. The final results show that the main contributions to the relative overall uncertainty are those closely related with the chemical aspects of the method, i.e. liquid-liquid extraction and standard addition calibration.
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Granada, E-18002 Granada, Spain.
authors.forename: Gracia
authors.initials: G
authors.lastname: Bagur
authors.forename: Mercedes
authors.initials: M
authors.lastname: Sánchez-Viñas
authors.forename: Domingo
authors.initials: D
authors.lastname: Gázquez
authors.forename: Miguel
authors.initials: M
authors.lastname: Ortega
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero