title: A uniform nonlinearity criterion for rational functions applied to calibration curve and standard addition methods.
abstract: Rational functions of the Padé type are used for the calibration curve (CCM), and standard addition (SAM) methods purposes. In this paper, the related functions were applied to results obtained from the analyses of (a) nickel with use of FAAS method, (b) potassium according to FAES method, and (c) salicylic acid according to HPLC-MS/MS method. A uniform, integral criterion of nonlinearity of the curves, obtained according to CCM and SAM, is suggested. This uniformity is based on normalization of the approximating functions within the frames of a unit area.
authors.affiliation: Department of Oncology, The University Hospital in Cracow, 31-501 Cracow, Poland.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Michałowska-Kaczmarczyk
authors.affiliation: Department of Analytical Chemistry, The University of Seville, 41012 Seville, Spain.
authors.forename: Agustin G
authors.initials: AG
authors.lastname: Asuero
authors.affiliation: Department of Analytical Chemistry, The University of Seville, 41012 Seville, Spain.
authors.forename: Julia
authors.initials: J
authors.lastname: Martin
authors.affiliation: Department of Analytical Chemistry, The University of Seville, 41012 Seville, Spain.
authors.forename: Esteban
authors.initials: E
authors.lastname: Alonso
authors.affiliation: Department of Analytical Chemistry, The University of Seville, 41012 Seville, Spain.
authors.forename: Jose Marcos
authors.initials: JM
authors.lastname: Jurado
authors.affiliation: Faculty of Engineering and Chemical Technology, Technical University of Cracow, Warszawska 24, 31-155 Cracow, Poland. Electronic address: michalot@o2.pl.
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Michałowski
keywords: Calibration; Chemical analysis; Curve fitting; Rational functions; Standard addition