Layer-by-layer self-assembling copper tetrasulfonated phthalocyanine on carbon nanotube modified glassy carbon electrode for electro-oxidation of 2-mercaptoethanol

This paper describes the electrocatalytic activity of layer-by-layer self-assembled copper tetrasulfonated phthalocyanine (CuPcTS) on carbon nanotube (CNT)-modified glassy carbon (GC) electrode. CuPcTS is immobilized on the negatively charged CNT surface by alternatively assembling a cationic poly(diallyldimethylammonium chloride) (PDDA) layer and a CuPcTS layer. UV–vis absorption spectra and electrochemical measurements suggested the successive linear depositions of the bilayers of CuPcTs and PDDA on CNT. The surface morphology was observed using scanning electron microscopy. The viability of this CuPcTS/PDDA/CNT modified GC electrode as a redox mediator for the anodic oxidation and sensitive amperometric determination of 2-mercaptoethanol (2-ME) in alkaline conditions is described. The effect of number of bilayers of CuPcTS/PDDA and pH on electrochemical oxidation of 2-ME was studied. The proposed electrochemical sensor displayed excellent characteristics towards the determination of 2-ME in 0.1 M NaOH; such as low overpotentials (− 0.15 V vs Ag/AgCl), linear concentration range of 3 × 10− 5 M to 6 × 10− 3 M, and with a detection limit of 2.5 × 10− 5 M using simple amperometry.

► Carbon nanotubes (CNT) were drop-dried on glassy carbon electrode (GCE).
► Copper tetrasulfonated phthalocyanine (CuPcTS) was deposited on CNT/GCE.
► Layer-by-layer self-assembling method is used for depositing CuPcTS.
► Electrocatalytic oxidation of 2-mercaptoethanol (ME) was studied at this electrode
► The detection limit of ME at modified electrode was 25 μM by amperometry.