Separation and electrochemical detection of paracetamol and 4-aminophenol in a paper-based microfluidic device

[Display omitted] ► Low cost and simple paper-based microfluidic device with electrochemical detection. ► Only two steps are necessary for the construction of the device, construction of the hydrophobic walls and gold sputtering. ► The substrate works as a separation platform and makes the separation of paracetamol and 4-aminophenol. ► Paper works as a filter and no sample pre treatment is necessary to perform the analysis. ► Baseline separation of the analytes can be achieved by injecting the sample at 12mm from the working electrode. The present work describes the construction and application of a simple, low cost and sensitive microfluidic paper-based device with electrochemical detection for the detection of paracetamol and 4-aminophenol. The separation channels of a width of 2.0mm were created on paper using a wax printing process to define the regions of the device. A baseline separation level of the analytes can be obtained in 0.1molL−1 acetate buffer solution at pH 4.5 and by injecting 500nL of the standard solutions at 12mm from the working electrode. The electrochemical detection system was created at the end of the channels through a process known as sputtering. The previously separated analytes were detected at the end of the hydrophilic separation channel by applying a potential of 400mV vs. pseudo Au on the working electrode. Experimental variables such as type of paper (cation exchanger and n1), pH, sample volume, applied potential and distance of sample injection were evaluated and, under the conditions of higher response, it was possible to obtain detection limits of 25.0 and 10.0μmolL−1 for paracetamol and 4-aminophenol, respectively.