Dulcin

This method of detection is at its most sensitive if the absorption maximum (A a,) of the sample molecule is exactly at the wavelength of the UV light employed for irradiation. The further lies from this the less radiation is absorbed and the lower the sensitivity of detection. If the compound does not absorb at the wavelength of radiation or if it possesses an absorption minimum just there then such components are not detected by this method. Figure 4C illustrates this with the sweeteners saccharin and dulcin as examples. 

Fig. 4 Explanation of the fluorescence-quenching effect [2]. — (A) chromatograms of the same quantities of saccharin and dulcin observed under UV 254 light, (B) schematic representation of fluorescence quenching, (C) spectral reflectance curves of saccharin and dulcin.

Fig. 25 Calibration curve for the determination of dulcin by fluorescence quenching and absorption [2],...

Drying methods, diethyl phthalate, 31, 2 magnesium ethoxide, 31, 2 Dulcin, 31,10... 

There is a recent trend towards simultaneous CE separations of several classes of food additives. This has so far been applied to soft drinks and preserved fruits, but could also be used for other food products. An MEKC method was published (Lin et al., 2000) for simultaneous separation of intense sweeteners (dulcin, aspartame, saccharin and acesulfame K) and some preservatives (sorbic and benzoic acids, sodium dehydroacetate, methyl-, ethyl-, propyl- and isopropyl- p-hydroxybenzoates) in preserved fruits. Ion pair extraction and SPE cleanup were used prior to CE analysis. The average recovery of these various additives was 90% with good within-laboratory reproducibility of results. Another procedure was described by Frazier et al. (2000b) for separation of intense sweeteners, preservatives and colours as well as caffeine and caramel in soft drinks. Using the MEKC mode, separation was obtained in 15 min. The aqueous phase was 20 mM carbonate buffer at pH 9.5 and the micellar phase was 62 mM sodium dodecyl sulphate. A diode array detector was used for quantification in the range 190-600 nm, and limits of quantification of 0.01 mg/1 per analyte were reported. The authors observed that their procedure requires further validation for quantitative analysis. 

The well-known antipyretic phenacetine (I) and the sweetening agent dulcine (II) are derivatives of p-phenetidine ... 

Fig-1 Chemical structures of the intense sweeteners saccharin, sodium cyclamate, acesulfame-K, aspartame, alitame, dulcin, sucralose, and neohesperidin dihydrochalcone. 

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,... 

Reverse-phase chromatography was used by Lawrence and Cbarbonneau (16) for the separation of cyclamate from saccharin, aspartame, acesulfame-K, alitame, sucralose, and dulcin. The system consisted of a Supelcosil LC-18 column and gradient elution of 0-100% mobile phase B [20 mM KH2P04 (pH 3.5) acetonitrile, 8 2 v/v] in mobile phase A [20 mM KH2P04 (pH 5.0) acetonitrile, 97 3 v/v]. 

Herrmann et al. (24) used ion-pair chromatography for the determination of cyclamate. The efficiency of LiChrosorb RP-18 and Hypersil MOS 3 with a mobile phase of 5 mM tetrabutylammonium p-toluenesulfonate, pH 3.5, mixed with 12% methanol for the separation of cyclamate from other sweeteners was investigated. With the first column, cyclamate separated from saccharin, but the second was the recommended column for the analysis of cyclamate, saccharin, aspartame, and dulcin in a single run. 

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