Membrane separation in flow injection analysis : Gas Diffusion

A general expression is derived for the membrane transport process in a flow-through unit as commonly used in flow injection systems. The validity of the formulae was tested for gas-diffusion membranes by using compounds with different volatilities such as ammonia, carbon dioxide and acetic acid. Several microporous hydrophobic membranes were tested. A new module design is proposed

The optimum composition of pH-sensitive acceptor solution for membrane separation in flow injection analysis

Gas diffusion membranes are frequently used to transfer volatile protolytes from a donor to an acceptor solution. This transfer is attended by a change in [H+] or [OH− and an absorbance change of the acid-base indicator present. Conditions determining the linearity and the sensitivity of the calibration graphs are discussed

A generalized approach for the calculation and automation of potentiometric titrations Part 2. Redox Titrations

The very fast calculation procedure described earlier is applied to calculate the titration curves of complicated redox systems. The theory is extended slightly to cover inhomogeneous redox systems. Titrations of iodine or 2,6-dichloroindophenol with ascorbic acid are described. It is shown that correspondence between theory and practice is good as long as the relevant stability constants and redox potentials are known with sufficient accuracy