Perspex Stirred Cell

All experiments were carried out in a magnetically stirred batch cell (volume of 110 mL, membrane area 15.2 10 m ) at a pressure of 100 kPa (if not otherwise indicated), pressurised with nitrogen gas. A reservoir of 1.5 L volume was connected to the stirred cell. A photo of a Perspex stirred cell with reservoir, manufactured in the university workshop, is shown in Figure 4.1. 

Figure 4.1 Perspex stirred cell with reservoir.

For fractionation experiments, the perspex stirred cells (see Chapter 4 for equipment description) were operated directly from the nitrogen bottle without a reservoir. Membranes were floated in a beaker of MilliQ water, skin side down, for at least one hour to remove the glycerin coating. Then at least 300mL of MilliQ water were filtered through the membrane. The filtrate was analysed with UV and DOC to confirm full removal of glycerin. The membranes were reused up to 5 times and stored in 0.1 % sodium azide at 4 C. Pure water flux was measured after the filtration of 500 mM of MiUiQ water prior to each experiment. The filtration protocols for serial and parallel fractionation were described in Chapter 4. In this Chapter parallel fractionation results will be shown. 

Figure A2.1 Drawing of Perspex stirred cell- AU dimensions are in mm.

A pressure release valve is mounted on top of the stirred cell in case the pressure exceeds 300 kPa. Further, an inlet from the feed reservoir (Perspex, 1.5 L) and a manual pressure release valve are located on top of the cell. The cell is placed on a magnetic stirrer table for stirrer operation (see Figure A2.2 for stirrer calibration). The membrane is fitted on a porous support in the bottom of the cell. 

In solubilized systems in which the solubilizate has a significant water solubility it is of interest to know not only the distribution ratio of solubilizate between the micelles and water under saturation conditions but also at varying degrees of saturation of the system with solubilizate. Such information cannot, of course, be obtained using the solubility methods discussed in Section 5.2.1. A dialysis technique has been described by Patel and Kostenbauder [32] and with various modifications has become a widely used technique [33-41]. In principle, the surfactant solution is separated from an aqueous solution of the solubilizate by a membrane permeable to solubilizate but not to micelles. In a typical dialysis cell the membrane is clamped between two Perspex half cells of approximately 150cm capacity (see Fig. 5.2). Provision is made for stirring and pH control if... 

Large volumes of solutions, circulating through external thermostatted reservoirs were used. The entire set up was housed in an air thermostat and the half-cells were each stirred by small motor-driven Perspex helices. 

Tiselius (1941) applied the principle of isoelectric fractionation by electrical transport to proteins using the apparatus shown in Fig. 9. It was a 12-compartment perspex apparatus with parchment paper as cathodic, leather as anodic, and cotton flannel as intermediate membranes. Stirring was effected by horizontally oscillating glass rods. After the stationary state was reached, all compartments were emptied instantaneously and dmultaneously. A specird arrangement for that purpose was described. In Table I can be seen the separation which was effected between egg albumin and hemoglobin in 0.005 N sodium sulfate solution after a 24 hours run. It is seen that the separation was almost complete, only one cell containing both proteins. 

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