FLOW-INJECTION SPECTROPHOTOMETRIC DETERMINATION OF ASPARTAME IN DIETARY PRODUCTS

A how injection spectrophotometric method has been developed for the d etermination of aspartame in dietary products using ninhydrin as a col orimetric reagent. The reaction was conducted in a 1 + 1 v/v methanol- isopropanol medium also containing potassium hydroxide. The absorbance measurements were made at 603 nm. The results obtained for the determ ination of aspartame in table sweetener, pudding, gelatin, and refresh ment (i.e., a powder dissolved in water for drinking) are in good agre ement with the results obtained using a conventional manual procedure (correlation coefficient, r = 0.9984). Thirty-six results were obtaine d per hour, and the relative standard deviation was less than 3.5% (n = 6) for all samples. The detection limit (three times the signal blan k/slope) was 3.8 X 10(-5) mol l(-1) of aspartame.