Flow-Injection Analysis with Multiple-Pulse Amperometry for Simultaneous Determination of Paracetamol and Naproxen Using a Homemade Flow Cell for Screen-Printed Electrodes

This work reports the simultaneous determination of paracetamol and naproxen using multiple-pulse amperometric detection on a multi-walled carbon nanotube modified screen-printed electrode (MWCNT-SPE) adapted in a homemade flow-injection analysis (FIA) cell. A sequence of two potential pulses (+0.30 and +0.70 V for 70 ms each) was applied continuously in such a way that paracetamol is selectively oxidized at +0.30 V and both compounds (paracetamol and naproxen) are oxidized at +0.70 V. Current subtraction after using a correction factor was employed for determination of naproxen without the interference of paracetamol. The proposed FIA method presents high selectivity and sensitivity, adequate accuracy (results in agreement with high-performance liquid chromatography), elevated analytical frequency (90 h(-1)), and low-cost once a single SPE strip can be used during the whole working day adapted in a flow-cell.