Electrochemical Sensor for Detection of Para-Nitrophenol Based on Modified Porous Silicon

Abstract

The behavior of a modified porous silicon surface (PSi) with polythiophene (PTh) for para-nitrophenol (p-NPh) detection by cyclic voltammetry was studied. Nitrophenols are organic compounds which are the most used in the production of pesticides but also in the dyes and pharmaceuticals. In particular, p-NPh is a toxic derivative of the parathion insecticide and is considered as major toxic polluant because it is soluble and stable in water so it can affect soil. Porous silicon was prepared by electrochemical etching and it was modified by an oxide layer. PTh films were grown on this surface using electropolymerization in acetonitrile in the presence of thiophene monomer.The morphology of the fabricated PSi/PTh hybrid structures were characterized by scanning electron microscopy (SEM). Cyclic voltammetry and amperometry were used to study the proposed electrochemical p-NPh sensor. The performance of the proposed sensor was tested under differents conditions and we note a very high sensitivity; in particular, the linearity of the sensor for the detection of para-nitrophenol was observed from 3×108 to 1.5 ×104M with a detection limit of 6×109M.