title: Enantioseparation of four amide herbicide stereoisomers using high-performance liquid chromatography.
abstract: The chirality of herbicides has been the focus of research. However, there is little information on the enantioseparation of amide herbicides with different chiral elements. In this study, the need for different chiral stationary phases (CSPs), mobile phases, temperatures and flow rates for the separation of napropamide, acetochlor and propisochlor was discussed in detail and compared to metolachlor. Resolution of C-chiral enantiomers was easier than that of axial-chiral enantiomers. Metolachlor and acetochlor could achieve baseline separation only on AY-H and AS-H columns, respectively. Propisochlor had satisfactory separations on OD-H and AS-H columns. Napropamide was separated on OJ-H, AY-H and AS-H columns. Both the structures of the compounds and CSPs and the interactions between them played significant roles in the enantioseparations. Molecule dockings were also used to elucidate the separation mechanisms. C-chiral enantiomers had perfect symmetry in their optical properties, whereas the axial-chiral enantiomers did not. The elution order for napropamide, acetochlor and propisochlor, with a single chiral location, was R- prior to S-. These results were the first that compare the enantioseparations of four amide herbicides with different chirality, and they provided the absolute configurations for the herbicides. The paper also illustrated certain mechanisms for enantioseparations.
authors.affiliation: MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Jingqian
authors.initials: J
authors.lastname: Xie
authors.affiliation: MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Division of Engineering and Applied Science, W. M. Keck Laboratories, California Institute of Technology, 1200 East California Blvd., Pasadena, CA, 91125, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.affiliation: MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Fangjie
authors.initials: F
authors.lastname: Guo
authors.affiliation: MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address: wliu@zju.edu.cn.
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
mesh_terms: D000081:Acetamides / Q000737:chemistry / Q000302:isolation & purification; D000577:Amides / Q000737:chemistry / Q000302:isolation & purification*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry / Q000302:isolation & purification*; D009281:Naphthalenes / Q000737:chemistry / Q000302:isolation & purification; D013237:Stereoisomerism; D013696:Temperature; D014052:Toluidines / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D000081:Acetamides; D000577:Amides; D006540:Herbicides; D009281:Naphthalenes; D014052:Toluidines; C470819:propisochlor; C043377:acetochlor; C010909:devrinol; C051786:metolachlor
keywords: Absolute configuration; Amide herbicides; Chirality; Enantioseparation; Separation mechanisms