Aspartame sample preparation

Two main standards were developed, one for the sweeteners showing UV absorption, i.e. acesulfame, aspartame and saccharin,36 and a separate standard for cyclamate37 which does not show a substantial UV absorption. Both standards use HPLC and propose specific sample preparation procedures. HPLC is also the suitable technique for the quantitative determination of sucralose.38... 

On plate A you will spot samples of (1) phenylalanine, (2) aspartic acid, (3) leucine, (4) aspartame in Equal, and (5) the hydrolyzed aspartame you prepared in step no. 1. On plate B you will spot samples of Diet Coke on lanes (1) and (4), aspartic acid on lane (2), aspartame in Equal on lane (3), and the hydrolyzed aspartame you prepared previously on lane (5). 

Procedure Separately inject equal 20-p.L portions of Impurity Standard Preparation and Sample Preparation into the chromatograph, and record the chromatograms (the approximate retention time of 5-benzyl-3,6-dioxo-2-piperazineacetic acid is 4 min, and the approximate retention time of Aspartame is 11 min). Measure the peak area response of 5-benzyl-3,6-dioxo-2-piperazineacetic acid in each chromatogram. Calculate the percentage of 5-benzyl-3,6-dioxo-2-piperazineacetic acid in the sample by the formula... 

Preparation and Wy is the weight, in milligrams, of Aspartame taken for the Sample Preparation. 

Procedure Inject about 20-pL portions of the Other Related Substances Standard Preparation and the Sample Preparation into the chromatograph, and record the chromatogram for a time equal to twice the retention time of Aspartame. In the chromatogram obtained from the Sample Preparation, the sum of the responses of all secondary peaks, other than that for 5-benzyl-3,6-dioxo-2-piperazineacetic acid, is not more than the response of the Aspartame peak obtained in the chromatogram from the Other Related Substances Standard Preparation. 

Identification The infrared absorption spectmm of a potassium bromide dispersion of sample exhibits maxima only at the same wavelengths as those of a similar preparation of USP Aspartame Reference Standard. 

Optical (Specific) Rotation Determine as directed under Optical (Specific) Rotation, Appendix HB, using a solution containing 6.2 g of sample in sufficient 15 N formic acid to make 100 mL. Make the determination within 30 min of preparation of the Sample Solution. Divide the calculated specific rotation by 0.646 to correct for the Aspartame content in Aspartame-Acesulfame Salt. 

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