Abstract:
Glassy carbon electrodes or plates were modified with nanocomposites
consisting of cobalt tetraaminophenoxyphthalocyanine
(CoTAPhPc), reduced graphene oxide nanosheets (rGONs) and
multi-walled carbon nanotubes (MWCNTs). The modified electrodes
were characterized using cyclic voltammetry, scanning electrochemical
microscopy (SECM) and time-of-flight-secondary ion
mass spectrometer (TOF-SIMS). The electrocatalytic activity of the
modified electrode was tested for detection of L-cysteine. The
presence of CoTAPhPc on sequential layers of MWCNT and rGONs
resulted in improved detection currents compared to CoTAPhPc
alone or when MWCNT/rGONs are mixed in CoTAPhPc–MWCNT/
rGONs (mix)–glassy carbon electrode (GCE). CoTAPhPc–MWCNT–GCE
(without rGONS) showed higher sensitivity toward L-cysteine as
compared to the probes incorporating rGONs with a catalytic rate
constant of 4.62 104 M 1s 1 and a detection limit of 30 nM. The
presence of rGONs improved the stability of the electrode.
