Amperometric Determination of Catecholamines by Enzymatic Biosensors in Flow Systems.

Abstract: Four various biosensors based on flow enzymatic mini‐reactors containing one of the two different mesoporous silica powders (SBA‐15 or MCM‐41) modified by one of the two enzymes (laccase or tyrosinase) were used for the determination of L‐DOPA, dopamine, noradrenaline, and adrenaline. Dependences of peak currents on detection potentials, flow rates, injected volumes, reactor volumes, and analyte concentrations were studied and optimized. The silica powder of MCM‐41 with covalently bonded laccase (Lac) was found to be the best filling for the detection of catecholamines. Relative current response of such biosensor was: 100 % for dopamine, 32.1 % for L‐DOPA, 26.2 % for noradrenaline, and 0.71 % for adrenaline. Statistical evaluation of parallel determinations of studied analytes with this biosensor proved its good accuracy (RSD=1.82–5.18 %) and sensitivity (5.46–15.5 μmol L−1). Life time of the studied biosensors is several months. The practical applicability of Lac‐MCM41 biosensor was successfully verified by the determination of dopamine and noradrenaline in medical solutions for infusions. [ABSTRACT FROM AUTHOR]