Simultaneous determination of aspartame, acesulfame-K, saccharin, citric acid and sodium benzoate in various food products using HPLC-CAD-UV/DAD

A newly developed method for simultaneous determination of aspartame, acesulfame-K, saccharin, citric acid and sodium benzoate in various diet supplements and non-alcoholic beverages in a single run is presented. The analytes were analysed by high-performance liquid chromatography coupled to a charged aerosol (Corona CAD) and ultraviolet-diode array detectors simultaneously connected in series. Mass spectrometer MicrOTOF-QII from Bruker Daltonik (Bremen, Germany) was used to obtain the mass spectra for peak identifications. The method was validated using a Thermo Hypersil Gold-C18 column packed with 5 mu m shell particles (150 x 4.6 mm) and methanol-water with 0.05 % TFA gradient mobile phase at a flow rate of 0.80 mL/min. The elaborated method was validated for linearity, precision and accuracy. The analytical results obtained in the validation study were highly satisfying; the recoveries for the analytes studied ranged between 98.1 and 101 % and the precision values from 0.11 to 1.73 %. By these procedures, the three sweeteners (aspartame, acesulfame-K and saccharin), citric acid and sodium benzoate could be well separated and quantitatively determined in varied food products. Hundred millilitres of soft drinks contained on average 5.50 mg of aspartame, 6.38 mg of saccharin, 8.94 mg of acesulfame-K, 9.05 mg of sodium benzoate and 111 mg of citric acid. Citric acid was the most abundant additive in all the samples analysed except for table sweeteners, and its highest concentration was determined in diet supplements, i.e. 347 mg/g. The percentage of adequate daily intake realisation in case of all additives is lower than 10 %, except for sodium benzoate in isotonic drinks (10.1 %).