Cloud Point Extraction and Spectrophotometric Determination of Carbendazim Fungicide in Vegetable and Environmental Samples

A micelle-mediated cloud point extraction for carbendazim determination in vegetable and environmental samples using UV-Vis spectrophotometry was developed. Parameters of the proposed method (i.e., pH, extraction time, concentration of surfactant, concentration of ferricyanide, concentration of ferric chloride, extraction temperature, and sample volume) were optimized by UV-Vis spectrophotometry. In this study, the developed method was based on the oxidation reaction of carbendazim by the ferric ion (Fe³⁺) under acidic conditions, combined with potassium ferricyanide (K₃[Fe(CN)₆]) to form potassium hexacyanoferrate complexes or the Turnbull’s blue product quantitatively. The final products were solubilized into surfactant micelles, and carbendazim was determined by UV-Vis spectrophotometry at 685 nm after cloud point extraction. The analytical performance of the proposed method was obtained under optimal conditions. The limits of detection and quantification were found to be 0.12 and 0.41 mg/L, respectively. Precision factors were expressed as intra-day (1.6%) and inter-day (7.2%) variations over three replications. Furthermore, the proposed method was applied to the determination of carbendazim in environmental samples such as tap water, underground water, surface water, and in vegetable samples such as garlic, shallot, dried chili, celery, and peanuts. Recovery was obtained in the range of 83–113%.