If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

Equilibrium Modeling of Mixtures of Methanol and Water

$29.00 plus tax (Refund Policy)

Buy Article:

Abstract:

An understanding of the species that form in mixtures of alcohol and water is important for their use in liquid chromatography applications. In reverse-phase liquid chromatography the retention of solutes on a chromatography column is influenced by the composition of the mobile phase, and in the case of alcohol and water mobile phases, the amount of free alcohol and water present. Previous and similar modeling studies of methanol (MeOH) and water mixtures by near-infrared (NIR) spectroscopy have found up to four species present including free MeOH and water and MeOH and water complexes formed by hydrogen bonding associations. In this work an equilibrium model has been applied to NIR measurements of MeOH and water mixtures. A high-performance liquid chromatography (HPLC) pump was coupled to an NIR flow cell to produce a gradual change in mixture composition. This resulted in a greater mixture resolution than has been achieved previously by manual mixture preparation. It was determined that five species contributed to the data. An equilibria model consisting of MeOH, H2O, MeOH(H2O) (log K H2O MeOH = 0.10 ± 0.03), MeOH(H2O)4 (log K 4H2O MeOH = −2.14 ± 0.08), and MeOH(H2O)9 (log K 9H2O MeOH = −8.6 ± 0.1) was successfully fitted to the data. The model supports the results of previous work and highlights the progressive formation of MeOH and water complexes that occur with changing mixture composition. The model also supports that mixtures of MeOH and water are not simple binary mixtures and that this is responsible for observed deviations from expected elution behavior.

Keywords: EFA; EQUILIBRIUM MODELING; EVOLVING FACTOR ANALYSIS; HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY; HPLC; HYDROGEN BONDING EQUILIBRIA; METHANOL/WATER MIXTURES; NEAR-INFRARED SPECTROSCOPY

Document Type: Research Article

DOI: http://dx.doi.org/10.1366/0003702053585444

Affiliations: Department of Chemistry, University of Newcastle, NSW, Australia

Publication date: March 1, 2005

More about this publication?
Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more