Preparation of a bisphenylureido-β-cyclodextrin-based column for simultaneous determination of ten residual triadimenol and other pesticide enantiomers in fruits and vegetables by HPLC

a new bis (5-chloro-2,4-dimethoxyphenylureido)-β-cyclodextrin stationary phase (MOCDP) was prepared via the reaction of mono -6-ethylenediamino-β-cyclodextrin with reactive isocyanate, and immoblization proccess. After characterization, MOCDP was used to resolve triazole pesticides, and we found that it had strong separation abilities for various triazoles ( R s = 1.42 ∼ 2.72). Especially, it could completely separate triazoles with two chiral centers into four enantiomers for the first time. Through optimizing the gradient elution program with ACN/MeOH/H 2 O, total ten triazole enantiomers ( R s = 1.75 ∼ 3.84) were simultaneously separated, including two hexaconazole, four triadimenol, and four metconazole enantiomers. Based on MOCDP column, a new HPLC method for the simultaneous quantification of the above ten residual triazole pesticide enantiomers in five fruits and vegetables (tomatoes, cucumbers, green peppers, apples, and bananas) was established with internal standard method and PDA detector at 220 nm. The elution order was triadimenol A (SR-,RS-) > triadimenol B (RR-,SS-) > hexaconazole (R-,S-) > metconazole A (RS-,SR-) > metconazole B (RR-,SS-). The good linear relationship ( R 2  = 0.9959 ∼ 0.9993) was observed in the range of 0.5 ∼ 50 mg/L (triadimenol B and metconazole B enantiomers) and 1.0 ∼ 100 mg/L (other enantiomers). The average recoveries of enantiomers were 82.58 %∼104.21 % ( n  = 15) with the RSDs of 1.55 %∼3.97 % ( n  = 5, intra -day) and 1.98 %∼4.42 % ( n  = 15, inter -day). The limits of detection and quantification were 0.03 ∼ 0.05 mg/kg and 0.10 ∼ 0.15 mg/kg, respectively. The chiral separation mechanism was also discussed through molecular simulation, revealing that the driving forces should be hydrogen bond, π-π stacking and inclusion complex derived from bisphenylureido groups and CD moiety in the chiral separations. This internal standard method had characterization of simple pretreatment, accurate quantification, and low cost.