Since the volume of mobile phase used for a separation is larger than the volume of stationary phase, Composition 2 will be prepared if the selected mobile phase is the aqueous phase. The amount of phases is different, but their compositions are identical. The chloroform-rich 13:7:4 system (Composition 3) separates in the 35% aqueous phase and 65% heavy organic phase ( Table 2.1, and right tube in Fig. The difference is that Composition 2 (rich in methanol and water) separates in 77% of the light aqueous phase and only 23% of the heavy chloroform-rich organic phase (left tube in Fig. The two systems belonging to the same tie-line separate into two phases that have exactly the same composition. It is very important to realize that a CCC separation performed with the 5:9:7, v/v/v, chloroform–methanol–water system will give exactly the same results as one done with the 13:7:4, v/v/v, system. Whatever liquid composition belonging to the tie-line is prepared, the aqueous phase is Composition 1 and the organic phase is Composition 5, both on the binodal curve on both ends of the tie-line. The only difference is the phase volume ratio. So, by definition, they separate into two liquid phases that have exactly the same compositions. Five particular compositions are shown in the diagram: Table 2.1 lists their respective compositions, and they all belong on the same tie-line. Figure 2.1 (top) shows the methanol–chloroform–water ternary phase diagram with the tie-lines in the biphasic domain. Here, we shall indicate how they should be used to minimize the solvent consumption. Ternary phase diagrams are used to represent all possible mixtures of three solvents they are described in Chapter 3.
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