Pyrocatechol Violet Based Sensor Enhanced By Carbon Nanotubes:the Catalysis And Its Application

(1) Pyrocatechol violet (PCV) was electrodeposited on single wall carbon nanotubes (SWCNTs) modified glassy carbon electrode (GCE) using continuous cycling between0and0.9V(vs. SCE). The as-prepared GCE/SWCNTs/PCV exhibited the enhanced electrochemical behavior of surface controlled mechanism. The apparent surface coverage of GCE/SWCNTs/PCV was at least24.5times higher than that obtained on bare GCE, namely2.7×1O-10and1.1×10-11mol cm-2. Owing to the remarkable synergistic effect of acid pre-treated SWCNTs and PCV, GCE/SWCNTs/PCV showed excellent electrocatalytic activity towards the oxidation of hydrazine at0.3V with fast amperometric response (<2s), broad linear range (150nM to0.4mM), good sensitivity (281mA M-1cm-2) and low detection limit (150nM) at signal-to-noise ratio of3. The sensor has been successfully applied to determine hydrazine in water and cigarette samples with good accuracy and precision. In addition, the morphology and the wetting property were characterized by scanning electron microscopy (SEM) and contact angle measurements, respectively.(2) The behavior of the PCV electrochemical polymerization was investigated by Surface Plasmon Resonance (SPR). Subsequently, PCV was used as redox-mediator and was electrodeposited on the surface of pencil graphite electrode (PGE) modified with SWCNTs. Owing to the remarkable synergistic effect of acid pre-treated SWCNTs and PCV, PGE/SWCNTs/PCV showed excellent electrocatalytic activity towards dihydronicotinamide adenine dinucleotide (NADH) oxidation at low potential (0.2V vs. SCE) with fast amperometric response (<10s), broad linear range (1.3μM to280μM), good sensitivity (146.2μA mM-1cm-2) and low detection limit (1.3μM) at signal-to-noise ratio of3. Thus, this PGE/SWCNTs/PCV can be further used to fabricate a sensitive and economic ethanol biosensor using alcohol dehydrogenase (ADH) via a glutaraldehyde/BSA cross-linking procedure.