Amperometric detection of caffeine and paracetamol on a dual screen printed electrode modified with mixed-valence ruthenium and cobalt oxides in flow-injection analysis

Abstract

It is found that the mixed-valence ruthenium and cobalt oxides (CoOx-RuOx) composite electrodeposited on screen printed electrode exhibits catalytic activity during caffeine and paracetamol electrooxidation. These compounds are oxidized at different potentials which provides selective voltammetric determination at simultaneous presence. A method of amperometric determination of caffeine and paracetamol on a dual electrode modified with CoOx-RuOx composite in a flow injection analysis is developed. The linear relationship between an analytical signal and analyte concentration is found in the range from 5×10-7 mol/l to 5×10-3 mol/l. Using a modified dual screen printed electrode as an amperometric detector in flow injection analysis allows to determine up to 360 samples/hour. The developed method has been tested in the analysis of some pharmaceuticals.