Quantification of Hydrofluoric Acid Species by Chemical-Modeling Regression of Near-Infrared Spectra

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• 作者：Christopher J. Thompson ; J. D. Sheldon Danielson ; and James B. Callis
• 刊名：Analytical Chemistry
• 出版年：1997
• 出版时间：January 1, 1997
• 年：1997
• 卷：69
• 期：1
• 页码：25 - 35
• 全文大小：272K
• 年卷期：v.69,no.1(January 1, 1997)
• ISSN：1520-6882

文摘

Near-infrared spectroscopy in the wavelength region 800-1100 nm has been applied to the measurement ofaqueous solutions of hydrofluoric acid over the concentration range 0.01-2.65 M and the pH range 2-13. Theanalysis is based on the detection of subtle perturbationsof the water spectrum which result from the presence ofthe acid and other species in solution. Spectralcharacterization of the hydrofluoric acid system was performedusing a spectrophotometric titration and multivariatemodel-based regression. Excellent agreement was observed between the spectra and a simple equilibriummodel describing the acid's dissociation. Fivespecies,including hydrofluoric acid, fluoride, bifluoride, hydronium, and hydroxide ions, were quantitated with estimation errors below 10 mM using this procedure. Inaddition, the species' spectral profiles were recovered,and optimum estimates of the system's equilibriumconstants were determined.