Cloud point extraction of carbendazim fungicide from strawberry samples and amperometric detection with boron doped diamond

[Display omitted] •CPE proved to be very satisfactory in the CBZ extraction from strawberry samples.•CBZ was extracted and preconcentrated to slightly more than nine-fold.•The method was duly validated and applied to real strawberry samples.•Boron-doped diamond electrode is quite efficient for the CBZ determination.•Strawberry washing/sanitizing methods rendered samples suitable for consumption. The cloud point extraction (Tergitol® surfactant) method was used for the first time to extract and preconcentrate the fungicide carbendazim (CBZ) from strawberry samples, while electrochemical detection (boron doped diamond electrode) in association with high performance liquid chromatography (HPLC-EC) was used for the determination of CBZ. The variables of bath temperature, ultrasonic stirring time, mass of NaCl and amount of surfactant were investigated using a 24 full factorial design. Limits of detection (LOD, S/N = 3) and quantification (LOQ) of 3.42 × 10−8 mol/L (or 6.54 µg/L) and 6.84 × 10−8 mol/L (or 13.1 µg/L), respectively, were obtained for the CPE processes, considering the value of the preconcentration factor obtained (9.12). The method was validated based on linearity, intra-day and inter-day recovery tests, accuracy and precision. The proposed method was applied to strawberry samples from local commercial establishments and different procedures for washing and sanitizing strawberry fruits were also evaluated.