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Selective Determination of Verapamil in Pharmaceutics and Urine Using a Boron‐doped Diamond Electrode Coupled to Flow Injection Analysis with Multiple‐pulse Amperometric Detection

MetadataDetails
Publication Date2018-04-25
JournalElectroanalysis
AuthorsAmanda Barbosa Lima, Lucas Franco Ferreira, Sandro L. Barbosa, Eric de Souza Gil, Rodrigo Amorim Bezerra da Silva
InstitutionsUniversidade Federal de Goiás, Universidade Federal de Uberlândia
Citations20

Abstract This work presents a simple and low‐cost method for fast and selective determination of Verapamil (VP) in tablets and human urine samples using a boron‐doped diamond working electrode (BDD) coupled to a flow injection analysis system with multiple pulse amperometric detection (FIA‐MPA). The electrochemical behaviour of VP in 0.1 mol L −1 sulfuric acid showed three merged oxidation peaks at around +1.4 V and upon reverse scan, one reduction peak at 0.0 V (vs. Ag/AgCl). The MPA detection was performed applying a sequence of three potential pulses on BDD electrode: (1) at +1.6 V for VP oxidation, (2) at +0.2 V for reduction of the oxidized product and (3) at +0.1 V for cleaning of the working electrode surface. The FIA system was optimized with injection volume of 150 μL and flow rate of 3.5 mL min −1 . The method showed a linear range from 0.8 to 40.0 μmol L −1 (R>0.99) with a low limit of detection of 0.16 μmol L −1 , good repeatability (RSD<2.2 %; n=10) and sample throughput (45 h −1 ). Selective determination of VP in urine was performed at+0.2 V due to absence of interference from ascorbic and uric acids in this potential. The addition‐recovery tests in both samples were close to 100 % and the results were similar to an official method.

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