title: Effect of alcohols and temperature on the direct chiral resolutions of fipronil, isocarbophos and carfentrazone-ethyl.
abstract: The enantiomeric separations of three pesticides fipronil (asymmetric nitrogen), isocarbophos (asymmetric phosphorus) and carfentrazone-ethyl (asymmetric carbon) were studied on cellulose-tri(3,5-dimethylphenylcarbamate) chiral stationary phase using high-performance liquid chromatography under normal phase. The mobile phase was n-hexane with alcohols including ethanol, n-propanol, iso-propanol, n-butanol and iso-butanol as polar modifiers. The flow rate was 1.0 mL/min with UV detection at 280, 225 and 230 nm for fipronil, isocarbophos and carfentrazone-ethyl respectively. The influence of the modifiers and their volume content and temperature from 0 to 50 degrees C on the separations was investigated. The chiral stationary phase showed excellent stereoselectivity for the two enantiomers of fipronil and isocarbophos and certain chiral recognition for carfentrazone-ethyl. Iso-propanol was more suitable for the chiral separation of isocarbophos and carfentrazone-ethyl, and iso-butanol was better for fipronil. The resolutions increased with the decreasing modifier content and temperature for all the three chiral pesticides.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Beijing 100094, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Shuren
authors.initials: S
authors.lastname: Jiang
authors.forename: Donghui
authors.initials: D
authors.lastname: Liu
authors.forename: Guifang
authors.initials: G
authors.lastname: Jia
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D002482:Cellulose / Q000031:analogs & derivatives; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008294:Malathion / Q000031:analogs & derivatives* / Q000302:isolation & purification*; D010575:Pesticides / Q000302:isolation & purification*; D048448:Phenylcarbamates; D011720:Pyrazoles / Q000302:isolation & purification*; D013696:Temperature; D014230:Triazoles / Q000302:isolation & purification*
chemical_list: D000438:Alcohols; D010575:Pesticides; D048448:Phenylcarbamates; D011720:Pyrazoles; D014230:Triazoles; C065943:cellulose tris-3,5-dimethylphenyl-carbamate; C427526:carfentrazone-ethyl; D002482:Cellulose; C082360:fipronil; D008294:Malathion