Open AccessGraphite-Polyurethane Composite Electrode Modified with Molecularly Imprinted Polymer for Determination of Diclofenac
Author(s) -
Abigail Vasconcelos Pereira,
Priscila Cervini,
Víctor Anthony García Rivera,
Éder Tadeu Gomes Cavalheiro
Publication year - 2022
Publication title -
journal of the brazilian chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.337
H-Index - 70
eISSN - 1678-4790
pISSN - 0103-5053
DOI - 10.21577/0103-5053.20210138
Subject(s) - molecularly imprinted polymer , detection limit , materials science , horizontal scan rate , nip , electrode , perchloric acid , molecular imprinting , nuclear chemistry , polyurethane , chemistry , chromatography , analytical chemistry (journal) , cyclic voltammetry , electrochemistry , selectivity , inorganic chemistry , organic chemistry , composite material , catalysis
A molecularly imprinted polymer (MIP) was prepared using the anti-inflammatory diclofenac (DCF) as a template. A non-imprinted polymer (NIP) was also prepared as a control. These MIP and NIP were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET), revealing a higher porosity in the first. Then both were used in the modification of graphite-polyurethane composites electrodes (GPUE). Differential pulse anodic stripping voltammetry was used for DCF determination at GPUE-MIP-DCF containing 2.5% (m/m) of the modifier in perchloric acid, pH = 2.0, after previously optimized conditions such as 300 s of accumulation time, +0.2 V accumulation potential (vs. SCE (saturated calomel electrode)), 50 mV pulse amplitude and 10 mV s–1 scan rate. A linear dynamic range from 0.010 to 0.20 μmol L–1 and a limit of detection (LOD) of 0.99 nmol L–1 were found, using GPUE-2.5-MIP-DCF. DCF was determined in commercial pharmaceutical formulations and in synthetic urine samples, with recoveries between 101 and 102% (n = 3) and 101% (n = 3), respectively. The results agreed with the reference high-performance liquid chromatography (HPLC) within 95% confidence level, according to Student’s t-test. Interference from meclofenamic and mefenamic acids, which are structurally similar to DCF, was also evaluated. Interferences could not be totally avoided, but MIPs presented a considerable ability in discriminating the voltammetric response for DFC, despite the close structural similarity with the interferents.