Chiral separation of aryloxyphenoxy-propionate herbicides in a permethyl-β-cyclodextrin based column. Influence of temperature and mobile phase composition on enantioselectivity

LUBOMIRSKY, ESTER; DI LORETO, H.; PADRÓ, J. M.; CASTELLS, C. B.

ELECTROPHORESIS

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2017

0173-0835

Weused a permethyl-β-cyclodextrinchiral stationary phase under reversed-phase conditions for thechiral separation of four aryloxyphenoxy-propionate herbicides(fenoxaprop-p-ethyl,quizalofop-p-ethyland tefuryl and haloxyfop-p-methyl)with mixtures of methanol, ethanol, 2-propanol, n-propanol,tert-butanol,or acetonitrile and water as mobile phases and investigated theinfluence of mobile phase composition and column temperature (from 0to 50 ºC) on the separation. Theretention factors (k)and selectivity factors (α)of all the herbicides investigated decreased with increasingtemperature. The lnαvs.1/T and lnk vs. 1/T plots for the enantiomers of the chiral pesticides werelinear within the range of 0?50 ºC with all alcohol/water mixturesconstituting the mobile phase, but the lnkvs. 1/T plots were nonlinear for all the enantiomers chromatographedin acetonitrile/water mixtures. The thermodynamic parameters based onlinear van?t Hoff plots were calculated. The influenceoftemperatureand mobile phase compositionon the enantioseparation of the solutes has rarely been consideredsimultaneously. The temperature and the solvents used in the mobilephase, however, were found to have a profound effect on theenantioseparation of these herbicides.