[Simultaneous determination of aspartame and amino acids in fermented milk beverages by HPLC]

An RP-HPLC method for the simultaneous determination of aspartame and amino acids in fermented milk beverages were established. Samples were prepared by mixing with methanol at a ratio of 1:1 and centrifuged at 4,000 r/min for 15 min. Ten microL supernatant was moved into a sample tube, dried and derivatized according to PICO-TAG procedure developed by Waters. A Novapak C18 column (3.9 mm x 150 mm) was used instead of PICO TAG column and the gradient elution program was modified correspondingly. Column temperature was maintained at 38 degrees C and the components were detected at 254 nm. Linearity for aspartame at the range in 1-100 mg/L is A = 333 C + 20 with r = 0.9996 where A is the integrated area of chromatographic peak of aspartame and C is the corresponding mass concentration. Repeatability for 8 injections was tested and the RSD of 3.2% was obtained. The recovery of aspartame for 5 samples with the method ranged from 94.2% to 98.7%.