This setup is useful only for laboratory experiments, and is set up as follows. Following Figure 1, a U-tube cell is used, and some type of carrier, perhaps dissolved in CH2Cl2, is placed in the bottom of the tube. That is the organic membrane phase. Two aqueous phases are placed in the arms of the U-tube, floating on top of the organic membrane. With a magnetic stirrer rotating at fairly slow speeds, in the range of 100 to 300 rpm, the transported amounts of materials are determined by the concentrations in the receiving phase. Stability is maintained so long as the stirrer is not spinning too quickly.