Sensitive catecholamine measurement using a monoenzymatic recycling system Original Research Article

A sensitive detection system for catecholamines based on a bioelectrocatalytic redox cycle was developed. The monoenzymatic modification procedure combines electrode platinization with a direct adsorption process of quinoprotein glucose dehydrogenase onto the platinized electrode surface. The recycling system proved to be sensitive in the lower nanomolar concentration range for catecholamines with the following order of sensitivity: dopamine > noradrenaline > adrenaline. Response rate is high (t90% < 20 s) and operational stability can be provided for more than 15 days. The electrode preparation method is suited for the fabrication of microelectrodes. Such modified microelectrodes showed comparable sensing characteristics to the macroelectrodes; however, the lower detection limit is improved (1 nmol/l dopamine).