Resumo em inglês The most relevant advances on the analytical applications of chemically modified electrodes (CME) are presented. CME have received great attention due to the possibility of electrode surface modification including chemisorption, composite generation and polymer coating. In recent years, the interest in CME has increased overall to improve the sensitivity and selectivity of the electroanalytical probes, considering the electron mediator incorporation and the new conducting (mais) polymers development. The general procedures employed for the electrode modification and the operational characteristics of some electrochemical sensors are discussed.
Simulação de espectros de ressonância paramagnética eletrônica (RPE) através do programa NLSL/ Simulation of electron paramagnetic resonance (EPR) spectra using the non-linear least squares program NLSL
Resumo em inglês EPR users often face the problem of extracting information from frequently low-resolution and complex EPR spectra. Simulation programs that provide a series of parameters, characteristic of the investigated system, have been used to achieve this goal. This work describes the general aspects of one of those programs, the NLSL program, used to fit EPR spectra applying a nonlinear least squares method. Several motion regimes of the probes are included in this computational t (mais) ool, covering a broad range of spectral changes. The meanings of the different parameters and rotational diffusion models are discussed. The anisotropic case is also treated by including an orienting potential and order parameters. Some examples are presented in order to show its applicability in different systems.