The usage of food additives must respect the general legislation in force in the country and requires a reliable analytical method for surveillance. This research aimed to develop a high-performance liquid chromatography with diode array detection (HPLC-DAD) method for the simultaneous determination of seven food additives and caffeine in powdered drinks. Three factors likely to affect the chromatographic separation, namely, mobile phase composition at the beginning (x1, 0-10% of the amount of methanol in the phosphate buffer) and the end (x2, 60-100% of the amount of methanol in the phosphate buffer) of the gradient program and pH (x3, 3-7), were evaluated with the aid of a Box-Behnken Design (BBD). Subsequently, multi-response optimizations for chromatographic resolutions (Rs) and analysis time were performed using the response surface methodology (RSM) in conjunction with the desirability function (DF). Complete separation (Rs > 1.5) of seven food additives and caffeine was achieved in less than 16 min by applying 8.5% methanol in the phosphate buffer at the beginning and 90% at the end of the gradient program, in pH 6.7. The developed method was validated with low limits of detection (ranging from 1.16 mg kg-1 (sodium saccharin) to 3.00 mg kg-1 (acesulfame potassium)), low limits of quantification (ranging from 3.86 mg kg-1 (sodium saccharin) to 10.02 mg kg-1 (acesulfame potassium)), high precision (CV < 4%), and high accuracy (recoveries from 95 to 101% at 80, 100, and 120% of the target concentration). The method was successfully used to assess the seven food additives and caffeine in commercially available powdered drinks.
Keywords: Box–Behnken Design; HPLC; food additives; multi-response optimization; powdered drinks.