"Biomimetic-electrochemical-sensory-platform" for biomolecule free cocaine testing.

A biomimetic cocaine sensor was fabricated by using poly(p-phenylene) (PPP) with cyclodextrin (CD) units in the backbone and poly(ethylene glycol) (PEG) side chains (PPP-CD-g-PEG). The sensory platform was constructed by one step surface modification of glassy carbon electrode with PPP-CD-g-PEG by drop coating. The electrochemical measurements are based on the formation of CD-cocaine inclusion complex on the surface resulting in a significant decrease in electron transfer capacity of the selected redox probe. The changes in the surface features due to cocaine binding were explored via electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry and electrochemical impedance spectrometry. The sensor exhibited linearity in the range of 25-200 nM cocaine, LOD was calculated as 28.62 nM (n = 5) according to 3Sb/m formula. Finally, the sensory platform was successfully applied for the cocaine analysis in synthetic urine samples and correlated with the chromatographic method.