ABSTRACT
The method consists in separating compounds dissolved in an initial liquid phase by contacting it with an immiscible solvent and by assembling the species in distinct fractions of the two solvents. The method consists in carrying out multiple liquid-liquid extractions at countercurrent. The process is carried out in a quite characteristic apparatus called Craig’s apparatus. Such apparatus comprises a certain number of cavities which in turn, comprise each of the two immiscible phases into which the solutes undergo partition. During the process, the two phases are grouped separately by handling the apparatus by rotation, specially conceived for this operation. Finally, the solutes are less or more separated since they are assembled in great part in each solvent. The chapter presents a thorough description of Craig’s apparatus and a theoretical study of this methodology. The latter permits the calculation of the concentrations of the different solutes in the different solvents step by step. The theoretical study given is exactly that of the beginning of the plates theory applying to the partition chromatography, as it will be seen later.
