Bioaffinity-Based Method for Catecholamines Determination with Amperometric DNA Sensor

A bioaffmity-based method for the determination of adrenaline and dopamine involving immobilized renatured DNA incorporated into the amperometric biosensor was developed. With the help of spectrophometry and voltammetry data, it was found that the composition of complexes formed with catecholamines and their stability constants were changing with concentration from [KAL(2)] to [KA(2)L], where KA - catecholamine, L - base pare, and lg beta(eff) = 10.1-13.5. The high affinity of adrenaline and dopamine to the immobilized renatured DNA molecule was revealed, thereby making it possible to run effective concentration of KA from the analyzed solutions of low concentration including multicomponent fluids. The minimum reporting level was found to be 5.5.10(-9) (adrenaline) and 2.0.10(-8) (dopamin) mol/L, respectively. The proposed method is characterized by high sensitivity, reproducibility (relative accuracy does not exceed 5%), and single determination time shorter than 30 min.