Stripping Voltammetric Determination of Choline Based on Micro-Fabricated Composite Membrane

A novel stripping voltammetric method for the determination of non-redox ionic species is presented. Using choline ion (Ch+) as an example, we demonstrate how a micro machined PVC-NPOE gel membrane can be used to accumulate Ch+ ion under potentiostatic steady-state conditions. The amperometric stripping of the target ion can be carried out by any voltammetric method but we presently illustrate the principle using linear sweep voltammetry. The effect of accumulation time, accumulation potential and choline ion concentration has been examined. The present work also includes the quantitative study of an enzyme reaction generating choline, namely the reaction of calcium phosphocholine with alkaline phosphatase. With this experimental approach, μg ml-1 concentration level of alkaline phosphatase enzyme can be determined.