Preparação de fases estacionarias para CLAE com uma mistura de poli(dimetilsiloxano) e poli(metiloctadecilsiloxano) sorvidos e imobilizados por tratamento termico sobre silica / Synthesis of stationary phases for HPLC with a poly(dimethylsiloxane) - poly(methyloctadecylsiloxane) mixture sorbed and immobilized by thermal tratment onto silica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

In this work the conditions for the preparation of a stationary phase of use in reverse phase high performance liquid cromatography (RP-HPLC) with a mixture of poly(dimethylsiloxane) (PDMS) and poly(methyloctadecilsiloxane) (PMODS) sorbed and immobilized by thermal treatment (in an inert atmosphere) on Kromasil silica (spherical, 5 mm) were optimized. The stationary phases were evaluatied by chemical, physical and chromatographic tests and for stability in mobile phases having agressive conditions. The best conditions for preparation of the stationary phases were: sorption of 25 % PMODS and 25 % PDMS on to the silica, storing for 15 days and then immobilizing at 128 °C for 8 hours and 40 minutes. The stationary phases from these conditions showed efficiencies of 60000 and 38000 plates m for naphthalene and N,N-dimethylaniline and symmetrical peaks for acidic (phenol) and basic (N,N-dimethylaniline) compounds. A characterization study using Tanaka s test-mixture indicated the presence of residual silanols, but evaluation parameters were still resonable, compared to PMODS, PDMS and some commercials phases. In the stability tests the stationary phase was for stable 250 column volumes in the basic test, showing a decrease of efficiency (60 %) for naphthalene but little change in asymmetry for naphthalene and N,Ndimethylaniline. In the acid test the stationary phase maintained efficiency for 950 column volumes with some decrease in efficiency (10 %) but showed a small change in asymmetry after 400 column volumes for acenaphtene. However, the retention factor fell in both tests, showing partical loss of the polymeric mixture without changing the coverage of the support

ASSUNTO(S)

poly (dimethylsiloxane) poly (dimethylsiloxane) poli (metiloctadecilsiloxano) clae-fr poli (dimetilsiloxano) rp-hplc

ACESSO AO ARTIGO

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