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Graphene Quantum Dots/l‑Cysteine Coreactant Electrochemiluminescence System and Its Application in Sensing Lead(II) Ions
journal contribution
posted on 2014-02-12, 00:00 authored by Yongqiang Dong, Wanrong Tian, Shuyan Ren, Ruiping Dai, Yuwu Chi, Guonan ChenA new
coreactant electrochemiluminescence (ECL) system including
single-layer graphene quantum dots (GQDs) and l-cysteine
(l-Cys) was found to be able to produce strong cathodic ECL
signal. The ECL signal of GQD/l-Cys coreactant system was
revealed to be mainly dependent on some key factors, including the
oxidation of l-Cys, the presence of dissolved oxygen and
the reduction of GQDs. Then, a possible ECL mechanism was proposed
for the coreactant ECL system. Furthermore, the ECL signal of the
GQD/l-Cys system was observed to be quenched by lead(II)
ions (Pb2+). After optimization of some important experimental
conditions, including concentrations of GQDs and l-Cys, potential
scan rate, response time, and pH value, an ECL sensor was developed
for the detection of Pb2+. The new methodology can offer
a rapid, reliable, and selective detection of Pb2+ with
a detection limit of 70 nM and a dynamic range from 100 nM to 10 μM.