Selective extraction of fungicides from fruit samples with defective UiO-66 as solid-phase microextraction fiber coating

A defective UiO-66 with rich defect sites was synthesized by a modulator-induced defect formation approach and used as the solid-phase microextraction (SPME) fiber coating material. The extraction experimental results showed that the defective UiO-66 coating can selectively extract the fungicides chlorothalonil, vinclozolin, dimethachlon, procymidone and iprodione with a high adsorption capability. The superior adsorption capability can be attributed to hydrophobic, Lewis acid-base and hydrogen bonding interactions. After optimization, a SPME with the defective UiO-66 as the fiber coating combined with GC–MS detection was established for the sensitive and selective determination of the five fungicides in fruit samples. Under the optimized experimental conditions, the quantitative linear response was in the range of 0.83–300 ng g −1 , with the coefficients of determination in the range from 0.9970 to 0.9986 and the limits of detection between 0.25 and 9.0 ng g −1 for the analytes. The method was successfully applied for the determination of the fungicides in different fruit samples. Satisfactory method recoveries (82.7%-117.7%) and good precisions with the relative standard deviations being from 3.2% to 12% were achieved.