Electrochemical properties of spaghetti and forest like carbon nanotubes grown on glass substrates

Carbon nanotubes (CNTs) have been widely used in many fields of chemical analysis to achieve more sensitive detection systems. In this work, we performed fundamental studies on grown or bottom-up fabricated MWCNTs (both non-oriented and oriented configurations), showing how variables like orientation, density, underlayer deposition, or synthesis time strongly determine their behavior (physical, electrochemical and analytical) as transducers. The electrochemical performance of these surfaces was demonstrated by cyclic voltammetry and chronoamperometry of dopamine (DA) solutions in 0.1 M H2SO4. The carbon nanotubes surfaces pre-treated with 1 M HNO3 lead to increased signals, sensitivity and enhanced limits of detection (LOD). The grown working electrodes (WE) were reproducible and stable over the time. The peak variations gave RSD values of 8%, 4% and 3% for high-density spaghetti-like and ITO or Al underlayered forest-like MWCNTs grown for 30 min, respectively. This study highlighted the importance of controlling the synthesis variables to achieve better analytical parameters.