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.
ASJC Scopus subject areas
- Analytical Chemistry