Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides

indoxacarb

lambda-cyhalothrin

and simeconazole

were studied on cellulose tris-(3

5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions

such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane

flow rate and column temperature

on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb

2% iso-butanol for lambda-cyhalothrin

and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(

a

) of 1.69

1.82 and 1.70

respectively.The resolution factor(

Rs

) decreased as the flow rate increased from 0.4 to 1.1 ml·min

-1

.The retention factor(

k'

) and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding

π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral iden

tification

and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.