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.]. © 2018, Springer-Verlag GmbH Austria, part of Springer Nature

Simultaneous determination of tert-butylhydroquinone, propyl gallate, and butylated hydroxyanisole by flow-injection analysis with multiple-pulse amperometric detection

We report the first amperometric method for the simultaneous determination of tert-butylhydroquinone (tBHQ), propyl gallate (PG), and butylated hydroxyanisole (BHA) using flow injection analysis coupled to multiple-pulse amperometry. A sequence of potential pulses was selected in order to detect tBHQ, PG, and BHA separately in a single injection step at a glassy carbon electrode without the need of a preliminary separation. A mixture of methanol and 0.040 M Britton-Robinson buffer was used both as a carrier solution and for dilution of analyzed solutions before injection. The method is precise (RSD < 5%, n = 10), fast (a frequency of 140 injections h−1), provides sufficiently low quantification limits (2.51, 1.45, and 0.85 μmol L–1 for tBHQ, PG, and BHA, respectively) and can be easily applied without high demands on instrumentation. As a practical application, the determination of these antioxidants contained in commercial chewing gum samples was carried out by applying a simple extraction procedure. © 2017 Elsevier B.V

Determination of Total Phenols in Foods by Boron Doped Diamond Electrode

A robust electrochemical method to measure the total phenol content in food samples is presented. Under optimal condition, BDD electrode showed excellent performance to detect the oxidation of several phenols and does not present the drawback due to electrode fouling. The analytical method used to perform such measurement has been optimized and successfully applied in different food samples. The results obtained were compared with the standard Folin-Ciocalteau method