Preparation of a phenylcarbamoylethylenediureido-β-cyclodextrin-bonded phase for enantioseparation and determination of cyproconazole, metconazole and other triazole fungicides in fruits and vegetables by high-performance liquid chromatography

we reported a new phenylcarbamoylethylenediureido-β-cyclodextrin CSP (PUCDP) for HPLC, which was conveniently prepared by immobilizing the addition product of diethylenetriamino-β-CD with 3,5-dichlorophenyl isocyanate onto silica gel. After structural characterization, the chromatographic performance of PUCDP was preliminarily evaluated by using common 11 triazole pesticides as probes. The results showed that PUCDP had strong chiral separation abilities for all triazoles ( R s=1.44–3.70). Especially, it could first completely separate triazoles with two chiral centers such as cyproconazole, triadimenol, metconazole, paclobutrazol and bitertanol, into four peaks, respectively. Some effects on the separation and detection were investigated, including the composition of mobile phase, pH value, column temperature, and absorption wavelength. Based on comprehensive optimization of chromatographic conditions and a homemade PUCDP column, we established a new method for the simultaneous separation and determination of twelve triazole pesticide enantiomeric residues (flutriafol, cyproconazole, tebuconazole, and metconazole) in nine kinds of fruits and vegetables (apple, banana, orange, pear, cucumber, green pepper, tomato, wax gourd, cabbage). After simple QuEChERS pretreatment, samples were analyzed under the optimized conditions of a gradient elution program with acetonitrile-water (ACN H 2 O) containing 0.5 % triethylammonium acetate (TEAA) buffer (pH=6.30) as the mobile phase at a flow rate of 0.5 mL min -1 , a photo-diode array (PDA) detector at 220 nm, column temperature at 20 °C and an injection volume of 20 μL. The method exhibited good linear relationship ( R 2 =0.9941–0.9999) in the range of 0.5–60 mg l -1 for all triazole enantiomers. The limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.05 to 0.10 mg kg -1 and 0.15 to 0.30 mg kg -1 , respectively. The average recoveries of all enantiomers were 81.60 %-104.08 % with intra -day and inter -day relative standard deviations (RSDs) of 1.91 %-3.50 % ( n = 5) and 2.05 %-4.49 % ( n = 15), respectively. The determination of 54 actual samples indicated the practicality of the method. This simultaneous determination method could save analysis time, and reduce solvent consumption with high analysis efficiency. The excellent performance of PUCDP was mainly related to the rich hydrogen bonds (donors and acceptors), the large π-π stacking and the extended cavity derived from the diphenylurea groups, which was consistent with the results of AutoDock molecular docking.