Simultaneous determination of sinapic acid and tyrosol by flow-injection analysis with multiple-pulse amperometric detection

Abstract: This work describes a simple, fast (frequency of 170 injections h⁻¹), and low-cost method for the simultaneous determination of two antioxidants, sinapic acid and tyrosol, using multiple-pulse amperometric detection at a glassy carbon electrode incorporated in a flow-injection analysis cell. A sequence of potential pulses was selected to detect sinapic acid and tyrosol separately in the course of a single injection step. During the characterization of electrochemical detection, conditions for the determination of the two antioxidants (such as the injected volume and the flow rate) were studied and the analytical figures of merit were calculated. The repeatability (expressed as %) RSD was < 4.0% (n = 10) and excellent linearity was obtained across two concentration ranges from 1.0 to 100 μM; the limits of detection of sinapic acid and tyrosol were around 1.0 μM. Graphical abstract: [Figure not available: see fulltext.].