Synthesis, characterization and kinetics of catalytically active molecularly imprinted polymers for the selective recognition of 4-aminophenol

In the present work a selective molecularly imprinted polymer (MIP) for 4-aminophenol (4-APh) was synthesized by the bulk polymerization technique. Polymerization was carried out in a glass tube containing 4-APh, Fe(III)protoporphyrin(IX) (hemin, Fe(III)PPIX), methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA) and 2,2′-azo-bis-iso-butyronitrile (AIBN). The polymer block was ground and sieved (106 µm) and the 4-APh was removed from the polymer particles by leaching with a methanol/acetic acid (4:1, v/v) solution, which leaves a cavity in the polymer particles. Hemin was used as a synthetic material to mimic the active center of peroxidase creating a catalytically active molecularly imprinted polymer. The polymers were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and particle size analysis. The enzymatic performance of the imprinted polymer was evaluated based on kinetic parameters including Vmax and the Michaelis-Menten constant obtained from Lineweaver-Burk plots.No presente trabalho um polímero com impressão molecular (MIP) seletivo para 4-aminofenol (4-APh) foi sintetizado através de técnica de polimerização em bulk. A polimerização foi realizada em tubo de vidro contendo 4-APh, Fe(III)protoporfrina(IX) (hemina, Fe(III)PPIX), ácido metacrílico (MAA), etileno glicol dimetacrilato (EGDMA) e 2,2'-azo-bis-iso-butironitrila (AIBN). O bloco de polímero foi moído e peneirado (106 µm) e o 4-APh foi removido das partículas do polímero pela extração com solução de metanol/ácido acético (4:1, v/v), deixando uma cavidade nas partículas do polímero. A hemina foi usada como um material sintético para imitar o centro ativo da peroxidase, criando um polímero com impressão molecular cataliticamente ativo. Os polímeros foram caracterizados por espectroscopia no infravermelho, análises termogravimétricas, microscopia eletrônica de varredura e análise do tamanho das partículas. O desempenho enzimático do polímero impresso foi avaliado baseado em parâmetros cinéticos incluindo Vmax e constante de Michaelis-Menten obtidas pelo gráfico de Lineweaver-Burk.820825Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Synthesis, characterization and kinetics of catalytically active molecularly imprinted polymers for the selective recognition of 4-aminophenol

In the present work a selective molecularly imprinted polymer (MIP) for 4-aminophenol (4-APh) was synthesized by the bulk polymerization technique. Polymerization was carried out in a glass tube containing 4-APh, Fe(III)protoporphyrin(IX) (hemin, Fe(III)PPIX), methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA) and 2,2′-azo-bis-iso-butyronitrile (AIBN). The polymer block was ground and sieved (106 µm) and the 4-APh was removed from the polymer particles by leaching with a methanol/acetic acid (4:1, v/v) solution, which leaves a cavity in the polymer particles. Hemin was used as a synthetic material to mimic the active center of peroxidase creating a catalytically active molecularly imprinted polymer. The polymers were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and particle size analysis. The enzymatic performance of the imprinted polymer was evaluated based on kinetic parameters including Vmax and the Michaelis-Menten constant obtained from Lineweaver-Burk plots

Electrocatalytic Activity Of 4-nitrophthalonitrile-modified Electrode For The L-glutathione Detection.

The present work describes the substantial electrocatalytic activity of (NC)2C6H3-NHOH/(NC)2C6H3-NO redox couple-modified electrode toward the low voltage detection of l-glutathione (GSH), in neutral medium, at an applied potential of 0.4V versus Ag/AgCl. After optimizing the operational conditions, the sensor provided a linear response range for GSH from 8.0 up to 83.0 micromol L(-1) with sensitivity, detection and quantification limits of 54nA L micromol(-1), 2.7 micromol L(-1) and 8.0 micromol L(-1), respectively. The proposed sensor presented higher sensitivity when compared to other modified electrodes described in the literature and showed a stable response for at least 100 successive determinations. The repeatability of the measurements with the same sensor and different sensors, evaluated in terms of relative standard deviation, were 4.1 and 5.0%, respectively, for n=10. The developed sensor was applied for GSH determination in yeast extract and the results were statistically the same with those obtained by the comparative method described in the literature at a confidence level of 95%.47758-6

Phenol based redox mediators in electroanalysis

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPEAL - FUNDAÇÃO DE AMPARO A PESQUISA DO ESTADO DE ALAGOASFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADOThe building of chemically modified electrodes is attracting increasing interest over the past decades, with a large number of publications, in different applications. The present review focuses on a special class of surface modifiers based on activated p827230252CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPEAL - FUNDAÇÃO DE AMPARO A PESQUISA DO ESTADO DE ALAGOASFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPEAL - FUNDAÇÃO DE AMPARO A PESQUISA DO ESTADO DE ALAGOASFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO465389/2014-7145167600300000/391/20172014/50867-3The authors wish to thank the Brazilian financial agencies: CNPq, CAPES/PROCAD (grant no. 145167) , FAPEAL (grant no. 600300000/391/2017), FAPESP and INCT in Bioanalytics (FAPESP grant no. 2014/50867-3 and CNPq grant no. 465389/2014-7