Magnetite-platinum nanoparticles-modified glassy carbon electrode as electrochemical detector for nitrophenol isomers

A glassy carbon electrode was modified with magnetite and platinum nanoparticles stabilized with 3-n-propyl-4-picoline silsesquioxane chloride. This chemically-modified electrode is proposed for the first time for the individual or simultaneous electrochemical detection of nitrophenol isomers. Nanoparticles act as catalysts and also increase the surface area. The polymer stabilizes the particles and provides the electrochemical separation of isomers. Under optimized conditions, the reduction peak currents, obtained by differential-pulse voltammetry, of 2-, 3-, and 4-nitrophenol increased linearly with increases in their concentration in the range of 0.1-1.5 μmol L−1. In individual analysis, the detection limits were 33.7 nmol L−1, 45.3 nmol L−1 and 48.2 nmol L−1, respectively. Also, simultaneous analysis was possible for 2-, and 4-nitrophenol. In this case, the separation of the peak potentials was 0.138 V and the detection limits were 69.6 nmol L−1 and 58.0 nmol L−1, respectively. These analytical figures of merit evidence the outstanding performance of the modified electrode, which was also successfully applied to the individual determination of isomers in environmental and biological samples. The magnetite and platinum nanoparticles modified glassy carbon electrode was able to detect nitrophenol isomers at the ppm level in rain water and human urine samples.