Abstract
A selective electrochemical method was developed for the individual or simultaneous determination of acetaminophen and caffeine in phosphate buffer pH 6.0 on graphite and polyurethane screen-printed composite electrode (EIGPU) using Differential Pulse Voltammetry (DPV). The oxidation peaks of acetaminophen and the caffeine appeared at 0.3 V and 1.3 V(vs. pseudo-Ag/AgCl), respectively, showing the possibility of simultaneous determination of both analytes, at the EIGPU, besides the individual determination. Analytical curves for the simultaneous determination showed a linear response for both compounds. The acetaminophen presented a linear region in the concentration range 1.00 - 40.0 µmol L-1 with detection limit of 0.84 µmol L-1, and the caffeine presented a linear region, in the concentration range 4.00 - 200 µmol L-1 with detection limit of 1.6 µmol L-1. The proposed method was applied in the simultaneous determination of acetaminophen and caffeine in three pharmaceutical formulations, with results similar to those obtained using a HPLC method, at 95% confidence level (Student t-Test).
Highlights
Screen-printed electrodes (SPEs), which are used as economical electrochemical substrates, have gone through improvements over the past few decades with respect to both their format and their printing materials
In the case of simultaneous voltammetric analysis of acetaminophen and caffeine, due the caffeine is present in lower concentration in the pharmaceutical formulations when compared to the concentration of acetaminophen (65:500 mg), the oxidation peak is less intense and more difficult to detect
The same study was performed for acetaminophen with reasonable results up to 70 mV s-1
Summary
Screen-printed electrodes (SPEs), which are used as economical electrochemical substrates, have gone through improvements over the past few decades with respect to both their format and their printing materials. The present work describes the use of a screen printed electrode based on a graphite and polyurethane composite (EIGPU), and the demonstration of its analytical potentiality as an electroanalytical sensor, in the selective and sensitive determination of acetaminophen and caffeine by Differential Pulse Voltammetry (DPV) individually as well as simultaneously. The vegetable oil PU and screen printed electrodes have already been used, the novelty here is the preparation of printed electrodes using the PU‐graphite (GPU) composite and its application to a classical model This new form for using the GPU composite, once it has been used before in the determination of many analytes as a conventional working electrode,[49,50,51,52] but in the present approach the composite was used to construct the printed device as well as the electrical contacts of the SPE. To one of the imprints it was attached a silver epoxy strip (Conductive Silver Epoxy Kit, Electron Microscopy Sciences, USA) to serve as a pseudo-reference electrode
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