Enantioseparation and determination of triazole fungicides in vegetables and fruits by aqueous two-phase extraction coupled with online heart-cutting two-dimensional liquid chromatography.

A novel method for determination of triazole fungicides and their enantiomers in foods was developed by aqueous two-phase extraction (ATPE) coupled with two-dimensional liquid chromatography (2D-LC). With an aqueous two-phase system (ATPS) of ethanol/K2HPO4 as biphasic extractant, the effects of the ATPS composition, extraction temperature and time on extraction yields of triazole fungicides were investigated. Optimum conditions were concluded as follows: ethanol concentration 31% (w/w) and K2HPO4 concentration 21% (w/w), extraction temperature 60 °C, extraction time 21 min. Based on reversed-phase separation systems, a 2D-LC was constructed by optimizing chromatographic conditions and online heart-cutting procedures. As a result, eight triazole fungicides and their enantiomers were separated respectively on C18 and cellulose-tris (3,5-dimethylphenylcarbamate) stationary phases, revealing good linear relationship in the range of 0.1218-30.06 μg/mL (R2 ≥ 0.9984). The detection limits and recoveries were 0.03113-0.3525 μg/mL and 71.57-107.8%, respectively. The ATPE-2D-LC method was successfully applied to chiral analysis of triazole fungicides in fruits and vegetables.