title: Colourimetric characterisation of disposable optical sensors from spectroradiometric measurements.
abstract: Spectroradiometric measurements of reflectance and CIELAB hue-angle, were tested for K(I) determination using disposable optical sensors based on ion exchange mechanism. The linearisation of the sigmoidal response function, using a logistic regression, increases the linear range noticeably to 7.65 x 10(-8)-1.5 M and 1.22 x 10(-7)-1.5 M for CIELAB hue-angle and reflectance, respectively. The trueness of both procedures was demonstrated comparing it with results obtained by a DAD spectrophotometer used as a reference measurement procedure. The usefulness of the procedure was checked by analysing K(I) in different types of waters and beverages. Additionally, we studied the possible visual discrimination for the whole potassium range tested, obtaining the possibility of discriminating twelve groups of concentrations.
authors.affiliation: Solid Phase Spectrometry Research Group, Department of Analytical Chemistry, Campus Fuentenueva, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Lapresta-Fernández
authors.forename: R
authors.initials: R
authors.lastname: Huertas
authors.forename: M
authors.initials: M
authors.lastname: Melgosa
authors.forename: L F
authors.initials: LF
authors.lastname: Capitán-Vallvey