Enzymeless biosensors: uma nova área para o desenvolvimento de sensores amperométricos

The aim of this work is to describe the recent area that it has been developed for the construction of amperometric sensors, with the purpose to make possible a more effective electron transfer between enzyme and electrode. The advances reported in the literature will be described, such as enzymatic configurations that can be mimic using the chemistry of the artificial enzymes.

Polímeros biomiméticos em química analítica. Parte 1: preparo e aplicações de MIP ("Molecularly Imprinted Polymers") em técnicas de extração e separação

MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented.

Polímeros biomiméticos em química analítica. Parte 2: aplicações de MIP ("Molecularly Imprinted Polymers") no desenvolvimento de sensores químicos

The aim of this paper is the description of the strategies and advances in the use of MIP in the development of chemical sensors. MIP has been considered an emerging technology, which allows the synthesis of materials that can mimic some highly specific natural receptors such as antibodies and enzymes. In recent years a great number of publications have demonstrated a growth in their use as sensing phases in the construction of sensors . Thus, the MIP technology became very attractive as a promising analytical tool for the development of sensors.

Degradação eletroquímica do cloranfenicol em reator de fluxo

This paper reports a study of electrochemical degradation of the chloramphenicol antibiotic in aqueous medium using a flow-by reactor with DSA® anode. The process efficiency was monitored by chloramphenicol concentration analysis with liquid chromatography (HPLC) during the experiments. Analysis of Total Organic Carbon (TOC) was performed to estimate the degradation degree and Ion Chromatography (IC) was performed to determinate inorganic ions formed during the eletrochemical degradation process. In electrochemical flow-by reactor, 52% of chloramphenicol was degraded, with 12% TOC reduction. IC analysis showed the production of chloride ions (25 mg L-1), nitrate ions (6 mg L-1) and nitrite ions (4.5 mg L-1).

Desenvolvimento e avaliação de eletrodos de difusão gasosa (EDG) para geração de H2O2 in situ e sua aplicação na degradação do corante reativo azul 19

This work reports the development of GDE for electrogeneration of H2O2 and their application in the degradation process of Reactive Blue 19 dye. GDE produced by carbon black with 20% polytetrafluoroethylene generated up to 500 mg L-1 of H2O2 through the electrolysis of acidic medium at -0.8 V vs Ag/AgCl. Reactive Blue 19 dye was degraded most efficiently with H2O2 electrogenerated in the presence of Fe(II) ions, leading to removal of 95% of the original color and 39% of TOC at -0.8 V vs Ag/AgCl.

Polímeros impressos com íons: fundamentos, estratégias de preparo e aplicações em química analítica

Chemical imprinting technology has been widely used as a valuable tool in selective recognition of a given target analyte (molecule or metal ion), yielding a notable advance in the development of new analytical protocols. Since their discovery, molecularly imprinted polymers (MIPs) have been extensively studied with excellent reviews published. However, studies involving ion imprinted polymers (IIPs), in which metal ions are recognized in the presence of closely related inorganic ions, remain scarce. Thus, this review involved a survey of different synthetic approaches for preparing ion imprinted adsorbents and their application for the development of solid phase extraction methods, metal ion sensors (electrodes and optodes) and selective membranes.

Estudio hidrofóbico de soluciones acuosas diluidas de isómeros de pentanodiol a varias temperaturas a partir de datos volumétricos

Density of dilute aqueous solutions of 1,2 pentanediol, 2,4 pentanediol, 1,4 pentanediol and 1,5 pentanediol at 283.15, 288.15, 293.15, 298.15, 303.15 and 308.15 K in the concentration range 0.0000 to 0.0060 in mole fraction were determined by using Wood-Brusie type capillary neck pycnometers. The solute partial molar volume as a function of solute concentration for each system was correlated with a linear equation for each temperature to estimate the slope limit and the partial molar volume at infinite dilution, and the predominant hydrophilic-hydrophobic effect was found in this region.