Separation sugars

The use of a ternary mixture in the drying of a liquid (ethyl alcohol) has been described in Section 1,5 the following is an example of its application to the drying of a solid. Laevulose (fructose) is dissolved in warm absolute ethyl alcohol, benzene is added, and the mixture is fractionated. A ternary mixture, alcohol-benzene-water, b.p. 64°, distils first, and then the binary mixture, benzene-alcohol, b.p. 68-3°. The residual, dry alcoholic solution is partially distilled and the concentrated solution is allowed to crystallise the anhydrous sugar separates. 

McCabe-Thiele diagrams for nonlinear and more practical systems with pertinent inequaUty constraints are illustrated in Figures 11 and 12. The convex isotherms are generally observed for 2eohtic adsorbents, particularly in hydrocarbon separation systems, whereas the concave isotherms are observed for ion-exchange resins used in sugar separations. 

Amperometric parameters have been studied and optimized for sugar separations.57236 The orcinol reaction has also been used as a post-column detection system for sugars.237... 

A proven solution to the binder problem is to use water insoluble organic polymer binders instead of clay. For example cellulose acetates and cellulose ethers binders are successfully employed to make commercial zeolitic adsorbents for sugar separation in aqueous solutions [154, 205, 218-223, 225-226, 231-232, 238]. This technique allows the use of zeoHte adsorbents in aqueous separation processes. 

Figure 26-29 (a) Amperometric detection with macroscopic working electrode at the outlet of the capillary, (b) Electropherogram of sugars separated in 0.1 M NaOH, in which OH groups are partially ionized, thereby turning the molecules into anions. [From J. Ye and R. P Baldwin, Amperometric Detection In CapHary Electrophoresis with Normal Size Bectrodes," Anal. Chem. 1993,65,3525.]... 

PE Shaw. Handbook of Sugar Separation in Food by HPLC. Boca Raton, FL CRC Press, 1988. 

The different methods of arranging the filter paper in the chromatographic chamber have been applied to sugar separations descending, ascending,39 40 and circular or horizontal development.41 These methods and other techniques will be discussed below. Detailed descriptions of the equipment needed for paper chromatography are readily available.8... 

Although the methods useful for separating the methylated derivatives on paper do not differ radically from those of sugar separations, a decreased water solubility of these derivatives favors higher RF values. Generally, their movement on paper is recorded relative to the movement of tetra-O-methyl-D-glucopyranose as the standard, and the RF values are then Ra values.10 It should be noted that Ra has also been used with D-glucose as the reference compound.114 Solvent developers most com-... 

Figure 1. Extract from flavored potato chips. Sugars separated as anions by 1on exchange chromatography with a sodium hydroxide eluent and a pulsed amperometrlc detector. Lactose concentration in the extract Is 70 ppm. "Reproduced with permission from Ref. 13 Copyright 1983, Marcel Dekker. "...

Sugar separation by GC requires the preparation of volatile derivatives. Tappi Test Method T 249 pm-75 uses the alditol acetate derivitization (40). Peracetylated aldonitrile (4J) or trimethylsilane (42, 43) derivatives can also be prepared and separated by GC. Wood sugar analysis by GC may be useful for specialized problems, but the derivitization steps make it a time-consuming method for routine work. 

It is also possible to also use an NH2 bonded phase as an ion exchanger, because it will form the quaternary ion, in buffers between pH s of 2 to 6 (i.e., a weak cationic exchanger). This can also be a problem when attempting the sugar separation described earlier, if acidic components in the mixture inadvertently transform the NH2 to the form. The separation will not work as well, if at all. This, fortunately, is reversible by taking the column to pure water, then pass-... 

Byers, C. H. Sisson, W. G. DeCarli, II, J. P. Carta, G. "Pilot scale studies of sugar separations by continuous chromatography" Appl. Biochem. Biotech. 1989, 20/21 pp 635-654. 

D. Betteridge, N.G. Courtney, T.J. Sly, D.G. Porter, Development of a flow-injection analyzer for the post-column detection of sugars separated by high-performance liquid chromatography, Analyst 109 (1984) 91. 

USE Refining beet sugar separating crystallizable sugar... 

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