title: Monitoring the temperature of dilute aqueous solutions using near-infrared water absorption.
abstract: An alternative spectroscopic approach for monitoring the temperature of aqueous solutions is presented. The method is based upon the temperature-induced spectral changes undergone by the second overtone (around 960 nm) of the near-infrared (NIR) water absorption band. Single and multilinear regression analysis are tested in order to evaluate the predictive ability of temperature. A linear dependence is found when measurements are performed at a single wavelength, but a lower prediction error is obtained when multilinear models are applied. No matrix effects produced by moderately concentrated common dissolved ions are found in a broad range of pH. A signal-to-noise ratio allows a precision of 0.5 degrees C for temperature monitoring. A prediction error of 0.77 degrees C (single linear regression) and 0.25 degrees C (multilinear approach) are achieved in a range from 15 to 90 degrees C. Advantages in terms of instrumentation and data analysis required are discussed.
authors.affiliation: Laboratorio de Análisis de Trazas, Departamento de Química Inorgánica, Analítica y Química Física-INQUIMAE- Facultad de Ciencias Exactas y Naturales-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 3er. Piso., Buenos Aires, Argentina.
authors.forename: Eugenio H
authors.initials: EH
authors.lastname: Otal
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Iñón
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Andrade
mesh_terms: D000465:Algorithms; D002119:Calcium Carbonate; D002254:Carbonates / Q000737:chemistry; D002951:Citrates; D004338:Drug Combinations; D006851:Hydrochloric Acid / Q000737:chemistry; D008277:Magnesium Oxide; D008956:Models, Chemical; D015999:Multivariate Analysis; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013223:Statistics as Topic; D013696:Temperature; D013817:Thermography / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D002254:Carbonates; D002951:Citrates; D004338:Drug Combinations; C050615:Suby's G solution; D014867:Water; D008277:Magnesium Oxide; D012965:Sodium Chloride; C005686:sodium carbonate; D012972:Sodium Hydroxide; D002119:Calcium Carbonate; D006851:Hydrochloric Acid