Enantiomeric Separation Of Chiral Phenoxy Acid Herbicides By Capillary Electrophoresis

Capillary electrophoresis (CE) technology is a analysis method thathas been developed in recent years. CE shows many merits in chiralanalysis,which includes high separation efficiency, short analysis time,application to many kinds of analytes, the small injection volume, lessreagent consumption and easy operation etc. Capillary electrophoresis is avery promising chiral separation and analysis method. Phenoxy acidherbicides is the first successfully developed and widely applied inagriculture and forestry production, mostly with chiral, its enantiomer hasobvious differences in herbicide activity, environmental behavior,biological toxicity. Therefore, we study on enantiomeric separation ofchiral phenoxy acid herbicides by capillary electrophoresis.This experiment using capillary electrophoresis separated five kindsof phenoxy carboxylic acid compounds:2-phenoxypropionic acid(2-PPA),2-(4-chlorophenoxy)propionicacid(2,4-CPPA),2-(3-chlorophenoxy)propionic acid(2,3-CPPA), Dichlorprop, Silvex. We used the cyclodextrinas chiral selectors, including γ-cyclodextrin(γ-CD), β-cyclodextrin(β-CD),2-Hydroxypropyl-β-cyclodextrin (2-HP-β-CD).When using γ-CD as chiral selector,Dichlorprop,Silvex and 2,3-CPPA could be separated with perfect baseline(Rs>1.5),2,4-CPPAand2-PPA were only partly separated.(Rs=0.5/0.89)When using β-CD as chiral selector,2,3-CPPAand2-PPA could becompletely separated(Rs>1.5),2,4-CPPA was partly separated（Rs=0.41）.The remaining two samples could not be separated.When using2-HP-β-CD as chiral selector,2,3-CPPA and2-PPAcould be completely separated(Rs>1.5). The remaining three samplescould not be separated.In summary, the baseline separation of4kinds of phenoxy acidherbicides were achieved.But2,4-CPPA could not be completelyseparated in the above three chiral selector, separation degree reached thehighest point(Rs=0.5)with γ-CD as chiral selector.In the above three chiral selectors, γ-CD is the most suitable chiralselector.In100mmol/LSDS─40mmol/Lγ-CD─75mmol/L H3PO4,weachieved the baseline separation of Dichlorprop,Silvex and2,3-CPPA,Rswas8.27,3.42and2.83.2,4-CPPA and2–PPA were partly separated, Rswas0.89and0.5.This experiment developed the study of chiral separation of phenoxyacid by capillary electrophoresis.The result can be applied to thedetermination of solid samples,and laid the foundation for the study ofthis pesticide’s environmental behavior.