Buckypaper Sensors for Detection of Phthalates in Solutions

Regardless of many hazardous effects, phthalates are used as plasticizers in many plastic product-manufacturing processes. They can be leached out to its surroundings with time. Thus, a facile method of detection of phthalates in different environments is crucial. A film of highly conducting Multi-Walled Carbon Nanotubes (buckypaper) was developed and the Faradaic electrochemical impedance of the phthalate-adsorbed buckypaper was used as the detection parameter to identify the presence of phthalates. The detection was done by observing the change of Faradaic impedance in the Nyquist plot and with the shift in unique peak system displayed in the Bode Phase plot compared to the pristine buckypaper. With this technique, Di(2-ethylhexyl) phthalate, Dioctyl phthalate, and Di(2-propylheptyl) phthalate in methanol solutions was successfully detected. Sensitivity of this novel technique towards some other aromatic molecules such as xylene, bisphenol A, toluene, and naphthalene is negligible as they show low Faradaic impedance compared to buckypaper alone. The adsorption of phthalate esters onto the buckypaper increases interfacial charge transfer resistivity resulting low electric conductance. Therefore, with this technique a sensor could be developed to detect phthalates in solutions.