Three-dimensional hybrid networks of molecularly imprinted poly(9-carbazoleacetic acid) and MWCNTs for simultaneous voltammetric determination of dopamine and epinephrine in plasma sample

A novel hybrid networks of molecularly imprinted poly(9-carbazoleacetic acid) and multi-walled carbon nanotubes (MWCNTs) was developed applying the electro-polymerization technique for the simultaneous voltammetric determination of dopamine and epinephrine. A carbazole derivative, 9-carbazoleacetic acid, was synthesized and used as a monomer for the first time. Owing to the introduction of carboxyl group, as well as the π-conjugated rigid plane structure of 9-carbazoleacetic acid, the molecularly imprinted poly(9-carbazoleacetic acid) afforded sufficient non-covalent interactions with the templates, enabled a good selectivity of the sensor. The MWCNTs acted as the supportive material for the molecularly imprinted poly(9-carbazoleacetic acid), resulted in the high specific surface area and high conductivity of the sensing interface. The as-prepared hybrid networks exhibited enhanced sensitivity and selectivity in the simultaneous voltammetric determination of dopamine and epinephrine. Experimental parameters involved in the sensor fabrication process were evaluated. A wide linear range of 0.04 ∼ 70 μM were obtained for the simultaneous detection of dopamine and epinephrine. The developed sensor, that requires only 100 μL samples for analysis, was applied to detect dopamine and epinephrine simultaneously in rat plasma sample. The recoveries were found in the range from 97.15 % to 105.5 %, indicating a promising potential in medical care and biological applications.