Desenvolvimento de sensores eletroquímicos baseados em nanopartículas magnéticas recobertas com polímeros de impressão molecular para determinação sensível e seletiva de ácido fólico

• Autor(a) principal: Garcia, Sara Manente
• Data de Publicação: 2022
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/216441
• topic: MIPs magnéticos (mag-MIPs); Adsorção; Sensor eletroquímico; Ácido fólico e seus metabólitos

The present work aimed to develop an analytical method based on biomimetic systems for the selective determination of folic acid. The construction of the biomimetic system was done by means of molecularly imprinted polymers, better known as MIPs (Molecularly Imprinted Polymers) synthesized on magnetic nanoparticles (Fe3O4) in core-shell format (mag-MIPs). The nanoparticles were obtained by the polyol method, which resulted in monodisperse, uniform, hydrophilic, highly crystalline and colloidally stable particles. The mag-MIPS and the control polymers or mag-NIPs (Molercularly Non-Imprinted Polymers) were morphologically characterized (SEM, FTIR and BET analyses) and subjected to rebinding tests with solutions of different folic acid concentrations in order to check their analytical performance. After proving the higher efficiency of mag-MIPS, these materials were used as modifiers in carbon paste electrodes combined with graphene oxide (mag-MIP-GO/CPE sensor). Under optimized conditions and using square wave adsorptive voltammetry, the proposed sensor exhibited excellent response over a linear concentration range between 2.5 × 10-6 and 48 × 10-6 mol L-1 and a detection limit of 6.5 × 10-7 mol L-1 (triplicate run, S/σ = 3). The sensor was subjected to repeatability tests and interference studies, obtaining satisfactory results. The advantages obtained with the proposed method were high robustness, numerous analyses, renewal of the electrode surface by simple polishing, high sensitivity, selectivity, and low cost. Finally, the sensor was applied in different matrices (pharmaceutical formulations and river water samples), presenting recovery percentages close to 100%.