Flow-injection pulse amperometric detection based on ion transfer across a water-plasticized polymeric membrane interface for the determination of imipramine

A flow-injection pulse amperometric method for determining imipramine, based on ion transfer across a plasticized poly(vinyl chloride) (PVC) membrane, was developed. A four-electrode potentiostat with ohmic drop compensation was used, while a flow-through cell incorporated the four electrodes and the membrane, which contained tetrabutylammonium tetraphenylborate. The influence of the applied potential, the flow-injection variables and of the pH on the determination of imipramine was studied. In the selected conditions, a linear relationship between current peak height and imipramine concentration over a range of 1 × 10−6 to 8 × 10−5 M imipramine was found. Good repeatability and between-day reproducibility were obtained. No interference was observed on the part of some common ions and pharmaceutical excipients. The method proposed was applied satisfactorily to the determination of imipramine in pharmaceuticals and human serum.