title: Simultaneous Determination of Monoatomic Ions via Infrared Attenuated Total Reflection Spectroscopy in Aqueous Solution at Different Temperatures.
abstract: In this study, monoatomic and thus IR-inactive ions were determined via infrared attenuated total reflection (IR-ATR) spectroscopy including Cl(-), Na(+), Mg(2+), Ca(2+), K(+) and Br(-), next to the IR-active ion [Formula: see text] The determination of IR-inactive ions is enabled, as each ion influences the infrared spectrum of bulk water by organizing the water molecules within the solvation shell around the ionic species in a unique way. Furthermore, the influence of temperature was taken into account for the potential application of this analytical technique in real-world scenarios. Using chemometric data analysis, seven ions could be discriminated at temperatures ranging between 3 ℃ and 45 ℃. Finally, within a sample of seawater, Cl(-), Na(+), Mg(2+) and [Formula: see text] could be simultaneously quantified, while the concentrations of Ca(2+), K(+) and Br(-) remained below the achievable limits of detection.
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Rauh
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Germany boris.mizaikoff@uni-ulm.de.
authors.forename: Boris
authors.initials: B
authors.lastname: Mizaikoff
keywords: ATR; IR; Infrared spectroscopy; PCA/PCR; attenuated total reflection spectroscopy; chemometrics; hydration; infrared; principal component analysis/regression; principal components analysis; principal components regression; salt ions; seawater analysis