Rapid carbamazepine detection by means of a disposable electrochemical sensor based on a molecularly imprinted polymer

The presence of pharmaceuticals such as carbamazepine (CBZ) in water environments poses a threat, highlighting the importance of developing analytical tools for the detection and quantification of these compounds. In this work, for the first time a molecularly imprinted polymer (MIP) sensor was obtained on a screen-printed carbon electrode (SPCE) for the rapid detection of CBZ. This simple and portable voltammetric sensor was obtained by electropolymerization of 3,4-ethylenedioxythiophene (EDOT) as the functional monomer in the presence of CBZ as the template molecule. Using differential pulse voltammetry (DPV) as the detection method, the construction parameters were assessed and optimized. As a result, the optimal sensor was obtained performing the following steps: i) an activation with 50 mM of H₂SO₄, ii) an electropolymerization performing 20 cycles of cyclic voltammetry using 4.5 mM of EDOT and 1 mM of CBZ, iii) an extraction with HCl 0.1 M during 30 min, and iv) an incubation in PBS pH 10 during 15 min. A linear analytical response was obtained in the range of 1-50 μM, with a LOD of 0.58 μM. The prepared sensor showed high selectivity towards CBZ over pharmaceuticals with similar chemical structures (CBZ 10,11-epoxide, diclofenac and diltiazem), with a response under 5.5 % of that for CBZ. Additionally, its performance in real water samples was assessed, yielding good recoveries. Hence, an easy-to-use MIP-based sensor was successfully developed with potential applications for on-site monitoring of CBZ in the environment.