Analysis of nine kinds of sweeteners in foods by LC/MS

A simple and rapid method for the simultaneous determination of nine kinds of Sweeteners (acesulfame potassium, AK; sucralose, SUC; saccharin, SA; cyclamate, CYC; aspartame, APM: dulcin, DU; glycyrrhizic acid, GA; stevioside, STV; rebaudioside A, REB) in various foods by high-performance liquid chromatography-electrospray mass spectrometry (LC/ESI-MS) was developed. The LC separation was performed on a ZORBAX Eclipse XDB-C 18 (2,1 mm X 150 mm) with a mobile phase of 5 mmol/L dibutylammonium acetate (DBAA) and acetonitrile-water (8: 2) Mass spectral acquisition was done in the negative ion mode by applying selected ion monitoring (SIM). The sweeteners were extracted from foods with 0.08 mol/L phosphate buffer (pH 7.0)ethanol (1: 1), and the extract was cleaned up on a Sep-pak Vac C 18 cartridge after the addition of tetrabutylammonium bromide and phosphate buffer (pH 3.0). The recovery of the nine kinds of sweeteners from five kinds of foods fortified at the level 0,01 g/kg, 0.05 g/kg and 0.20 g/kg was 75.7-109.2%, and the between-day SD values were 0.5-10.99%. The quantification limits of AK, SA, CYC, APM and STV were 0.001 g/kg, and those of SUC, DU, GA and REB were 0.005 g/kg. A recovery test from each cleaned-up sample solution was necessary to detect ionization suppression.