Enantioseparation of selected chiral agrochemicals by using nano-liquid chromatography and capillary electrochromatography with amylose tris(3-chloro-5-methylphenylcarbamate) covalently immobilized onto silica

In this paper enantiomers of selected chiral agrochemicals representing various structural classes were separated by using nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) employing a capillary column packed with silica particles containing immobilized amylose tris(3-chloro-5-methylphenylcarbamate) (i-ADMPC) as a chiral selector (CS). Special attention was paid to peak dispersion in nano-LC and CEC instruments used in order to make comparison between these two techniques more reliable. Enantioseparations were studied utilizing methanol (MeOH) or acetonitrile-water (ACN-H2O), both containing 5 mM of ammonium acetate as the mobile phases (MPs). The tested chiral stationary phase (CSP), containing 20% (w/w) of the neutral CS onto native silica, allowed the generation of sufficiently strong electroosmotic flow (EOF) to observe separation of enantiomers of studied agrochemicals in a reasonable time also in CEC mode. Modestly higher efficiencies and enantiore-solutions were obtained in CEC than in nano-LC. Just a moderate preference of CEC over nano-LC in this particular study can be explained with a significant mass transfer resistance through the CSP that is caused due to high content of the CS in CSP. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, enantiomers of chiral agrochemicals were successfully separated using nano-liquid chromatography and capillary electrochromatography. The use of a capillary column packed with immobilized amylose tris(3-chloro-5-methylphenylcarbamate) as the chiral selector showed better performance in CEC than in nano-LC. The findings suggest the potential of CEC for enantioseparations in the analysis of chiral agrochemicals.