CYP450 biosensors based on screen-printed carbon electrodes for the determination of cocaine

A new electrochemical method has been described and characterized for the determination of cocaine using screen-printed biosensors. The enzyme cytochrome P450 was covalently attached to screen-printed carbon electrodes. Experimental design methodology has been performed to optimize the pH and the applied potential, both variables that have an influence on the chronoamperometric determination of the drug. This method showed a reproducibility of 3.56% (n = 4) related to the slopes of the calibration curves performed in the range from 19 up to 166 nM. It has been probed the used of this kind of biosensors in the determination of cocaine in street samples, with an average capability of detection of 23.05 ± 3.53 nM (n = 3, α = β = 0.05).