PREPARATION AND CHARACTERIZATION OF OCTADECYLAMINE-CONTAINING CARBON-PASTE ELECTRODES

An effective strategy for circumventing problems of interference by electroactive species during the,detection of hexacyanoferrate at the carbon:paste-electrode (CPE) is described. The concept relies on the. incorporation of octadecylamine within the carbon paste. The electrochemical characterization of the modified electrode (potential range, background current, stability, permselectivity) has been investigated by amperometry and linear scan and cyclic voltammetry in aqueous media with different ionic strengths and in hydroalcoholic media. The interference of analytes such as ascorbic acid, uric acid, and dopamine can be eliminated totally by appropriate adjustment of the amount of octadecylamine within the carbon paste matrix. The modified electrode was highly selective to hexacyanoferrate. Optical microscope observations of the CPE and modified CPE showed a higher density of graphite particles covered with liquid paraffin-octadecylamine layers at the latter. Development of biosensors using such modified electrodes is discussed.