TITLE:
Fitting Nonlinear Calibration Curves: No Models Perfect
AUTHORS:
Julia Martin, Alberto Romero Gracia, Agustín G. Asuero
KEYWORDS:
Calibration, Non Linear Calibration, Residual Analysis, Liquid Chromatography-Tandem Mass Spectrometry, Emerging Pollutants
JOURNAL NAME:
Journal of Analytical Sciences, Methods and Instrumentation,
Vol.7 No.1,
March
3,
2017
ABSTRACT: The study of the calibration of a series of compounds of environmental concern (six perfluoroalkyl compounds (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids), three preservatives (methyl-, ethyl- and propylparabens) and the brominated flame retardant hexabromocyclododecane) by LC-MS/MS has been carries out, with a view to their simultaneous determination in samples of environmental interest. In some cases nonlinear calibration curves are obtained, but restricting the concentration range a linear model may be used to fit the data. Residual analysis has been performed in order to verify which models fit the data better, opting for a compromise decision given the apparent complexity of residuals plots. As Box states there are no perfect models (but models that work better than others).