Study of electrooxidation and enhanced voltammetric determination of β-blocker pindolol using a boron-doped diamond electrode

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Pindolol (PND), an antihypertensive agent indicated for patients in the treatment of angina, hypertension, cardiac arrhythmias and recently consumed as doping agent by athletes, is electrochemically determined in this research by using a cathodically pretreated boron-doped diamond (CPT-BDD) electrode. The electrochemical response of PND studied via cyclic voltammetry on the BDD surface, shows an irreversible oxidation process. From cyclic voltammetric assays carried out at different potential scan rates, the electrochemical parameters number of electrons transferred and the apparent heterogeneous electron transfer rate constant (k0app) were determined. Additionally, chronoamperometric measurements performed at different PND concentration levels yielded the apparent diffusion coefficient of this molecule (Dapp) in 0.2 mol L−1 phosphate buffer solution (pH = 6.0). After a number of optimization steps, a differential pulse voltammetric (DPV) procedure for the sensitive determination of PND using the CPT-BDD electrode was developed. Under the optimum experimental conditions, the obtained analytical curve was linear in the wide concentration range from 0.04 to 10.0 μmol L−1 and a limit of detection of 26 nmol L−1 was also determined. The viability of the proposed voltammetric procedure was checked out towards the quantification of PND in pharmaceutical formulation samples and biological fluids. The successfully application of the proposed voltammetric procedure suggest the potentiality of this approach for field applications, such as control of pharmaceutics and monitoring of PND in biological samples from athletes subjected to anti-doping exams.