Membrane-Based Solid-Fluid Contacting

1 Membrane Adsorption, Membrane Chromatography Liquid-Solid Contacting 

This method of fluid-soUd contacting is now practiced commercially in the biotechnology industry. An early introduction to this technique is available in Brandt et al. (1988). A number of reviews are available (Thommes and Kula, 1995 Roper and Lightfoot, 1995). A book illustrating this technique was pubUshed sometime back (Klein, 1991). 

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Solid-contact pH sensors can be constructed by using polypyrrole [45,59] or polyaniline [92,96] as ion-to-electron transducer in combination with pH-selective membranes based on plasticized PVC [45,59,92,96]. The dynamic pH range of the sensors depend on the pH ionophore used in the plasticized PVC membranes, as follows tri-n-dodecylamine (pH 2-12) [45], tris(2-phenylethyl)amine (pH 4.5-12.6) [59], tris(3-phenylpropyl)amine (pH 4.6-13.2) [59], tribenzylamine (pH 2.5-11.2) [92,96], dibenzylnaphtalenemethylamine (pH 0.65-10.0) [96], dibenzylpyrenemethyl-amine (pH 0.50-10.2) [96]. Suggested applications include pH measurements in body fluids such as serum [45,96], whole blood [92], and cow milk [59]. 

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