A novel approach, ultrasound-assisted reverse micelles dispersive liquid–liquid microextraction (USA-RM-DLLME) followed by high performance liquid chromatography (HPLC) was developed for selective determination of acetoin in butter. The melted butter sample was diluted and homogenised by n-hexane and Triton X-100, respectively. Subsequently, 400 μL of distilled water was added and the microextraction was accelerated by 4 min sonication. After 8.5 min of centrifugation, sedimented phase (surfactant-rich phase) was withdrawn by microsyringe and injected into the HPLC system for analysis. The influence of effective variables was optimised using Box–Behnken design (BBD) combined with desirability function (DF). Under optimised experimental conditions, the calibration graph was linear over the range of 0.6–200 mg L−1. The detection limit of method was 0.2 mg L−1 and coefficient of determination was 0.9992. The relative standard deviations (RSDs) were less than 5% (n = 5) while the recoveries were in the range of 93.9–107.8%
