All-solid-state surfactant sensing electrode using conductive polymer as internal electric contact Original Research Article

An all-solid-state anionic surfactant electrode type was developed using teflonized graphite rods coated with electrochemically prepared polypyrrole film as electric connector support. The measuring membrane of the electrodes was made of ion-pairs formed with the appropriate anionic and cationic surfactants incorporated into plasticized poly(vinylchloride) film. Preparation procedure for the ion-pair is described briefly in the text. The electrochemical properties of the electrode were studied and the function of the electrode was tested. Due to the well defined charge transfer mechanisms at the graphite–polypyrrole-membrane interfaces the surfactant electrode showed good stability. The lower limit of detection was in the range of 0.5–1 μM in case of the different surfactants tested. Due to the relatively fast response time and the good stability of the electrode, a sample rate of 30 sample/h in flow-injection determinations could be achieved.