Oxidized thin aluminum films used as the polarized liquid-liquid interface support for norcocaine detection

In this work, the surface of thin (around 100 nm thick) porous aluminum film was thermally oxidized and used as the electrified liquid-liquid interface support. Constructed platforms provided quasi-sigmoidal voltammetric characteristic for the forward interfacial transport of all studied model ions (quaternary ammonium cations) typical for the microscopic liquid-liquid interfaces supported with pore(s) with a diameter exceeding the support thickness. Thin aluminum films before and after heat treatment were characterized using ion transfer voltammetry, scanning electron microscopy, optical profilometry and contact angle measurements. Finally, the utility of the constructed devices was verified during voltammetric norcocaine sensing in artificial and spiked real urine samples. Norcocaine gave a clear signal recorded within the available potential window and could be detected from the concentration equal to around 10 µM. The parameters such as limit of detection, limit of quantification, detection sensitivity, diffusion coefficient, and water/1,2–dichloroethane partition coefficient are also provided and tabulated.