Stationary phases of poly(methyl-3,3,3-trifluoropropylsiloxane) immobilized onto silica supports for reversed-phase high performance liquid chromatography: preparation and characterization

Author(s)

Liane Maldaner

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2010-02-25

Examining board members

Isabel Cristina Sales Fontes Jardim; Martha Bohrer Adaime; Maria Eliana Lopes Ribeiro de Queiroz; Susanne Rath; Ivo Milton Raimundo Júnior

• Advisor: Isabel Cristina Sales Fontes Jardim

Abstract

New fluorinated stationary phases (SP) were prepared through thermal or microwave immobilization of poly(methyl-3,3,3-trifluoropropylsiloxane) (PMTFS) onto 5 mm Kromasil silica particles. The immobilization conditions were optimized employing experimental design and resulted in 200 °C for 12 hours for thermal treatment and 126 °C (760 W) for 50 minutes for microwave irradiation. Physical-chemical characterization showed that the polymer was both physically adsorbed and chemically bonded to the chromatographic support, in both immobilization procedures, resulting in a percent carbon load of 9 % and 10 % for the SP immobilized by thermal treatment and by microwave irradiation, respectively. Chromatographic characterization showed that the SP developed presented efficiencies > 70 000 N m, hydrophobic characteristics, steric and methylene selectivity and small interactions between the basic compounds and the residual silanol groups. This reduction of the undesirable interactions can be associated to the presence of the fluorine atoms that promote different interactions with the basic compounds and thus reduce these effects. The fluorinated SP were selective for the separation of positional isomers and pharmaceuticals and are an attractive alternative to the classical reversed stationary phases (AU)