Graphite-Polyurethane Composite Electrode Modified with Molecularly Imprinted Polymer for Determination of Diclofenac

• Autor(a) principal: Pereira,Abigail V
• Data de Publicação: 2022
• Outros Autores: Cervini,Priscila, Rivera,Victor A. G, Cavalheiro,Éder T. G
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532022000300205
• topic: electrochemical sensor; differential pulse anodic stripping voltammetry; selectivity

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.