A selective spectrofluorimetric method for carbendazim determination in oranges involving inclusion-complex formation with cucurbit[7]uril

The increase in fluorescence intensity with respect to carbendazim that occurs as a result of supramolecular-complex formation between carbendazim and cucurbit[7]uril has been studied. This host–guest interaction has been employed to develop a sensitive and selective method for benzoimidazole-type pesticide determination in fruit samples. The association constant and stoichiometry of the complex formed are reported herein, and the influence of experimental variables, such as the pH or ionic strength of the solution, on complex formation and the presence of interfering substances is also discussed. Under the optimal conditions found, the developed method allows the detection of carbendazim at a 5.0 × 10−9 M level. To test the method, matrix solid phase dispersion was employed as a sample preparation method for carbendazim determination in orange samples with an RSD (%) (n = 3) value of 5%. The LOD and LOQ values calculated for real samples were 0.10 and 0.52 mg/kg, respectively, thus showing that the proposed method is sensitive enough to meet legal requirements.