title: Chromatographic evaluation using basic solutes of the silanol activity of stationary phases based on poly(methyloctylsiloxane) immobilized onto silica.
abstract: The chromatographic behaviors of some basic solutes were evaluated on stationary phases based on poly(methyloctylsiloxane) immobilized onto silica (PMOS-SiO(2)). The test solutes present both hydrophobic and hydrophilic properties. Evaluations of the pH effect used 80:20 v/v methanol/buffered mobile phase over the pH range of 5-11.5 with inorganic buffers such as borate, carbonate and phosphate and with organic buffers such as citrate, tricine and triethylamine. Evaluations in acidic mobile phases used 50:50 v/v and 30:70 v/v methanol/buffer (pH 2.5; 20 mmol/L) mobile phases. The buffer concentration effect used 65:35 v/v methanol/phosphate (pH 7; 20 and 100 mmol/L) mobile phases. The results are compared with those obtained with two chemically bonded stationary phases. The immobilized phases show greater contributions from an ion-exchange mechanism than do the commercial phases. The results indicate that the silanol activity of PMOS-SiO(2) stationary phases can be adequately evaluated by using appropriate basic probes and mobile phases having different pH, using different buffers.
authors.affiliation: Institute of Chemistry, University of Campinas, Campinas, SP, Brazil.
authors.forename: Endler M
authors.initials: EM
authors.lastname: Borges
authors.forename: Carol H
authors.initials: CH
authors.lastname: Collins
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation*; D011108:Polymers / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*
chemical_list: D011108:Polymers; D012821:Silanes; D012833:Siloxanes; C475630:poly(methyloctylsiloxane); C082343:silanol; D012822:Silicon Dioxide