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Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds
Published on: October 12, 2018
Study of complexation in methanol/water mixtures by infrared and Raman spectroscopy and multivariate curve
Carol A Holden1, Sally S Hunnicutt, Raymundo Sánchez-Ponce
1Department of Chemistry, Virginia Commonwealth University, PO Box 842006 Richmond, Virginia 23284-2006, USA.
Abstract:
The structure of the mobile phase in liquid chromatography plays an important role in the determination of retention behavior on reversed-phase stationary materials. One of the most commonly employed mobile phases is a mixture of methanol and water. In this work, infrared and Raman spectroscopic methods were used to investigate the structure of species formed in methanol/water mixtures. Chemometric methods using multivariate curve resolution by alternating least-squares analysis were used to resolve the overlapped spectra and to determine concentration profiles as a function of composition. The results showed that the structure of these mixtures could be described by a mixture model consisting of four species, namely, methanol, water, and two complexes, methanol/water (1:1) and methanol/water (1:4). The spectral frequencies and concentration profiles found from the Raman and infrared measurements were consistent with one another and with theoretical calculations.
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