Paper-based 2D configuration for the electrochemical and facile detection of paracetamol in wastewaters

Since 2020, human pharmaceuticals were included in the list of emerging contaminants from the UNESCO and their detection and elimination were incorporated in the 2030 Agenda for Sustainable Development Goal Targets. Among these, analgesic and antipyretic drugs are the most widely used drugs worldwide and, despite their advantages, unused or expired pharmaceuticals are a potential source of water pollution. Paracetamol is one of the most common drugs used for analgesic and antipyretic purposes and has been found to have a much higher concentration in water streams in many European countries. Considering that, an all-in-one paper-based 2 dimensional (2D) fluidic configuration, able to detect paracetamol, was developed in order to deal with environmental matrices without complex/expensive analytical procedures. An ad-hoc paper-based testing area, coupled with a channel was designed and wax-printed onto a porous filter paper. Successively three electrodes were screen-printed, and the whole system was applied for the detection of paracetamol in wastewaters (prior and after the filtration system) without pretreating the sample. In order to detect paracetamol with the easiest approach, the configuration of the paper-based device was optimized in terms of type of substrate used for printing, microfluidic paper strip length/width and combination of them in an integrated architecture, capable to detect paracetamol in the matrices tested in few seconds with a detection limit down to micromolar range, ca. 1 μM. The integrated device shown great promise for simple, fast, sensitive, and sustainable detection of paracetamol in its role of emerging contaminant, especially in the environmental matrices.