This paper describes the development of a sensor for the determination of metronidazole using a simple method involving the creation of nanoporous structures on gold electrodes followed by modification with self-assembled monolayers (SAMs) of thiols. The initial formation of oxidized gold species at pH 7.0 was followed by potentiodynamic reduction in order to obtain a nanostructured surface that was then modified with a SAM of cysteine. The sensor was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical techniques. Quantification of metronidazole was performed using optimized square wave voltammetry. Under the best analytical conditions, the sensor operated at -0.36 V showed a linear range of 50-300 µmol L-1 and a limit of detection (LOD) of 2.6 µmol L-1. Evaluation of selectivity demonstrated that the electrode provided higher sensiti...

An electrochemical sensor (CPE-IIHP) was developed for Cd(II) using a carbon paste electrode (CPE) impregnated with an ion-imprinted hybrid polymer (IIHP). A CPE-NIHP was also prepared for comparison. DPASV was used to optimize the sensor response and quantify Cd(II). The sensor presented a wide linear range from low concentrations of Cd(II): 1 to 100 ?g L?1 and high concentrations of Cd(II): 2.75 to 5.0 mg L?1. Ions such as Co(II), Pb(II), Ni(II), Zn(II), Fe(II), Fe(III), Sn(II) and Cu(II), showed no variation in the Cd(II) signal. The CPE-IIHP was successfully applied in river and drinking water analysis, revealing the great potential for its application.

The present work shows the synergistic application of reflectance spectroscopy and core-shell molecularly imprinted polymer (MIP) for rapid quantification of tartrazine in soft drinks. Studies evaluated the performance of the MIPs synthesized in the presence of silica nanoparticles unfunctionalized and functionalized with [3-(methacryloyloxy)propyl]trimethoxysilane. Although the use of functionalized silica nanoparticles promoted the highest adsorption capability of tartrazine, the material was found to be less selective when it was applied in real samples. Interestingly, the most accurate results were obtained via the application of the MIP synthesized in the presence of unfunctionalized silica nanoparticles (SiO2@MIP). The optimized core-shell MIP was also characterized by Raman spectroscopy and scanning electron microscopy. The use of direct reflectance spectroscopy in the analyte det...

A sensor based on molecularly imprinted polymers (MIP) was developed for determination of 3-(3,4-Dichlorophenyl)-1,1- dimethylurea (diuron). The MIP were synthesized by free radical polymerization in wich diuron acted as template, methacrylic acid (MAA) acted as functional monomer and ethylene glycol dimethacrylate (EGDMA) acted as crosslinker. For construction of the sensor, glassy carbon electrode was modified with Nafion® and MIP/NIP (non imprinted polymer) to see the contribution of MIP, as a film, in the diuron recognition. Differential Pulse Voltammetry was used to the quantification of diuron in a range of response 0.4 - 1.2 V in a PBS (pH=8). All parameters affecting the sensor were optimized. The sensor showed a linear response from 1.00x10-5 to 9.616x10-5 M in PBS 0.1 M (pH=8). The limit of detection was 0.58x10-5 mol L-1. The nanostructured sensor was prepared using carbon na...