A Carbon Nanotube Based Electrochemical Sensor for Sulfide Detection

Abstract Microbiologically influenced corrosion (MIC) is considered one of the major causes of oil and gas pipeline failures, costing billions of dollars annually. Despite the increasing research attention attracted to this area, in-situ detection and monitoring of MIC in real time has presented difficulties, due to the complexity of the corrosion processes resulted, directly or indirectly, from the ever evolving metabolic activities of microorganisms. In this work, an amperometric electrochemical biosensor based on a conducting polymer and carbon nanotubes was developed for detection and monitoring of hydrogen sulfide that can be generated by sulfate reducing bacteria, the main culprits of MIC. The single-walled carbon nanotubes (SWCNTs) are functionalized by a conductive polymer ‒ a polythiophene derivative, which enables the formation of carbon nanotube-polymer nanocomposite sensing layer with enhanced signal transduction capability. A cross-linking agent in optimized dosage was used to improve the water stability of the sensing layer without compromising its electric conductivity. Fast detection of sulfide was achieved with good sensitivity, attributed to the large active surface area of carbon nanotubes and excellent conductivity of the nanocomposite sensing layer. The sensor developed paved the way for further development of online sensors for monitoring MIC.