Authors: Endler M Borges Melvin R Euerby Carol H Collins
Publish Date: 2012/01/11
Volume: 402, Issue: 6, Pages: 2043-2055
Abstract
A novel stationary phase prepared by the thermal immobilization of polydimethylsiloxane onto the surface of silica PDMS–SiO2 has been described evaluated and compared with 229 commercially available RPLC stationary phases using the Tanaka column classification protocol The phase exhibited many unique chromatographic properties and based on the phases in the database was most similar to the fluoroalkylated phases aside from the obvious lack of fluoro selectivity imposed by the C–F dipole The phase exhibited classic reversedphase behaviour in acid mobile phase conditions and mixedmode reversedphase/cationexchange retention behaviour in neutral mobile phase conditions The phase exhibited acceptable stability at both low and intermediate pH conditions which should impart optimum chromatographic selectivity to the phase Retention of basic analytes was shown to occur by a “three site model” as proposed by Neue This new PDMS–SiO2 stationary phase is extremely interesting in that the dominancy of its hydrophobic and ionexchange interactions can be controlled by the influence of mobile phase pH buffer type and concentration The PDMS–SiO2 stationary phase may provide a complementary tool to reversedphase and HILIC stationary phases The present results highlight the fact that the type of buffer its concentration and pH can not only affect peak shape but also retention selectivity and hence chromatographic resolution Therefore in method development and optimization strategies it is suggested that more emphasis should be given to the evaluation of these mobile phase operating parameters especially when basic solutes are involvedThe authors acknowledge financial support and fellowships from the Brazilian Agencies FAPESP Fundação de Amparo a Pesquisa do Estado de São Paulo CNPq Conselho Nacional de Desenvolvimento Científico e Tecnológico and CAPES Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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