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Type: Artigo de periódico
Title: Effects of pH and temperature on the chromatographic performance and stability of immobilized poly(methyloctylsiloxane) stationary phases
Author: Borges, EM
Collins, CH
Abstract: The effects of mobile phase pH, temperature, buffer type and buffer concentration on the selectivity and stability of four stationary phases, with different PMOS loadings, prepared by the thermal immobilization of poly(methyloctylsiloxane) on to silica (PMOS-SiO2), were evaluated with both hydrophobic and hydrophilic basic solutes. These solutes show longer retention times at near neutral pH, where both the silanols and the basic solutes are partially ionized, and shorter retention times in more alkaline pH, where the silanols are mostly ionized and the basic solutes are not ionized. Increases in temperature and buffer concentration also result in shorter retention times. These PMOS-SiO2 stationary phases are quite stable at low pH and are also stable at ambient temperature (23 degrees C) using pH 7 phosphate. The PMOS-SiO2 stationary phases are more stable at higher pH using triethylamine (pH 11) and borate (pH 10) buffers than with phosphate and carbonate buffers. Temperature increases stationary phase degradation, while buffer concentration has a minimal effect on stationary phase degradation, indicating that these PMOS-SiO2 stationary phases have stabilities similar to the equivalent chemically bonded phases. (C) 2012 Elsevier B.V. All rights reserved.
Subject: Basic solutes
Chemical and thermal stability
Silanol activity
Country: Holanda
Editor: Elsevier Science Bv
Citation: Journal Of Chromatography A. Elsevier Science Bv, v. 1227, n. 174, n. 180, 2012.
Rights: fechado
Identifier DOI: 10.1016/j.chroma.2012.01.001
Date Issue: 2012
Appears in Collections:Unicamp - Artigos e Outros Documentos

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