Saccharin separation from benzoic acid

Fig. 3.138. Electropherogams showing the separation of caffeine (1), aspartame (2), brilliant blue FCF (3), green S (4), sorbic acid (5), benzoic acid (6), saccharin (7), acesulfame K (8), sunset yellow FCF (9), quinoline yellow (10), carmoisine (11), ponceau 4R (12), black PN (13), using 20 mM carbonate buffer, pH 9.5 containing (a) no SDS, (b) 50 mM SDS, (c) 75 mM SDS. A 48.5 X 50 /tm I.D. fused-silica capillary was used and absorbance was measured at 200 nm. Reprinted with permission from R. A. Frazier et al. [184],...

Reverse-phase chromatography has been used extensively for the determination of saccharin. Smyly et al. (30) and Eng et al. (39) used /rBondapak Cl 8 and 5% acetic acid for the determination of saccharin. Based on this work, an Association of Official Analytical Chemists (AOAC) collaborative study was conducted, and the method using a mobile phase buffered to pH 3 with sodium acetate and modified with 3% isopropanol was adopted. Webb and Beckman (61) used this method successfully for the separation of saccharin from aspartame, caffeine, sodium benzoate, and artificial colors and flavors. Veerabhadrarao et al. (27) added methanol to the mobile phase (methanol acetic acid water, 4 1 1, v/v) for improved separation of saccharin from caffeine, benzoic and p-hydroxybenzoic acids, vanillin, aspartame, acesulfame-K, and dulcin. Saccharin was also determined using LiChrosorb Cl8 and 4 6 v/v methanol phosphate buffer,... 

FIGURE 13-7. Effect of pH on the retention times of the beverage additives , benzoic acid , aspartame , caffeine o, saccharin. Conditions are the same as Figure 13-6 with the pH of the acetic-acid component adjusted with 50% sodium hydroxide to the desired pH. (Note Actual separation will depend upon the quality of the mobile phase and column packing.) (Reproduced from reference 6 with permission.)... 

Saccharin may be separated from benzoic acid by extraction of the latter in strongly buffered solution of pH 4 0. ... 

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