Synthesis And Application Of A Peroxidase-like Molecularly Imprinted Polymer Based On Hemin For Selective Determination Of Serotonin In Blood Serum.

This work reports the preparation of a molecularly imprinted polymer (MIP) for selective catalytic detection of serotonin (5-hydroxytryptamine, 5-HT). The process is based on the synthesis of polymers with hemin introduced as the catalytic center to mimic the active site of peroxidase. The copolymer MIP, containing artificial recognition sites for 5-HT, has been prepared by bulk polymerization using methacrylic acid (MAA) and hemin as the functional monomers, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. For the determination of 5-HT, a flow injection analysis system coupled to an amperometric detector was optimized using multivariate analysis. The effects of different parameters, such as pH, buffer flow rate, buffer nature, peroxide concentration and sample volume were evaluated. After optimizing the experimental conditions, a linear response range from 1.0 up to 1000.0 micromolL(-1) was obtained with a sensitivity of 0.4nA/ micromolL(-1). The detection limit was found to be 0.30 micromolL(-1), while the precision values (n=6) evaluated by relative standard deviation (R.S.D.) were, respectively, 1.3 and 1.7% for solutions of 50 and 750 micromolL(-1) of 5-HT. No interference was observed by structurally similar compounds (including epinephrine, dopamine and norepinephrine), thus validating the good performance of the imprinted polymer. The method was applied for the determination of 5-HT in spiked blood serum samples.631170-

Dispositivo Sensor, Processo De Preparação Do Dispositivo, Método Para Detecção De Artemisinina Em Amostras Multicomponentes, E Uso

DISPOSITIVO SENSOR, PROCESSO DE PREPARAÇÃO DO DISPOSITIVO MÉTODO PARA DETECÇÃO DE ARTEMISININA EM AMOSTRAS MULTICOMPONENTES, E USO. A presente invenção tem como objeto proporcionar um dispositivo amperométrico para detecção de artemisinina e o processo de produção do mesmo. O dispositivo é de fácil operação, susceptivel a miniaturização e portabilidade. Esse sensor proporciona diagnosticar alterações dos níveis de artemisinína, in foco de forma mais precisa, rápida, simples e seletiva de que os sistemas atualmente existentes. Em especial, o dispositivo compreende uma base de pasta de carbono, a partir da imobilização de hemina em sílica gel modificada com óxido de titánio, capaz de quantificar níveis baixos de artemisinina (ARN) em uma amostra em especial uma amostra multicomponente como, por exemplo, um isolado, um extrato vegetal, uma fração enriquecida, uma composição fitoterápica, uma composição cosmética e uma composição farmacológica. A presente invenção se situa nos campos da química e farmácia.BRPI0900203 (A2)G01N27/327G01N27/406BR2009PI00203G01N27/327G01N27/40

A Very Low Potential Electrochemical Detection Of L-cysteine Based On A Glassy Carbon Electrode Modified With Multi-walled Carbon Nanotubes/gold Nanorods.

A nanohybrid platform built with multi-walled carbon nanotubes and gold nanorods, prepared via a cationic surfactant-containing seed-mediated sequential growth process, in aqueous solution, on a glassy carbon substrate has been successfully developed to be used in the electrocatalytic oxidation of L-cysteine (Cys). The nanohybrid was characterized by transmission electron microscopy, Raman spectroscopy and electrochemical measurements. Cyclic voltammetry results had shown that the modified electrode allows the oxidation of Cys at a very low anodic potential (0.00 V vs. Ag/AgCl). The kinetic constant kcat for the catalytic oxidation of Cys was evaluated by chronoamperometry and provided a value of 5.6×10(4) L mol(-1) s(-1). The sensor presents a linear response range from 5.0 up to 200.0 µmol L(-1), detection limit of 8.25 nmol L(-1) and a sensitivity of 120 nA L µmol(-1).50202-

Analysis of Styrene Polymerization Without Surfactant and N2 Gas in Cylindrical Flask.

<div><p>The conditions of chemical synthesis can be crucial for polymerization of styrene in such a way that it can be produced latex beads at nanometric range (ϕ < 400nm). In this work, it will be analyzed how the absence of N2 and surfactant will result in colloidal particles with high affinity to agglomerate forming two kinds of nanostructured assemblies: colloidal crystals and nanowires. Four syntheses were realized and four parameters were changed: temperature, impeller speed, and initiator and styrene concentrations. The dispersion was filtered and coated on glass slides by evaporation induced self-assembly (EISA) process. Morphology and topography were observed at Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) respectively. They show how the synthesis conditions play a vital a role on the formation of self assembly nanostructures that can be applied as templates for sensors and biomaterials devices.</p></div