Web Release Date: October 2,
Anodic Electrochemiluminescence of CdTe Quantum Dots and Its Energy Transfer for Detection of Catechol Derivatives
MOE Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, P.R. China
Received for review May 7, 2007. Accepted August 25, 2007.
Abstract:
This work reported for the first time the anodic electrochemiluminescence (ECL) of CdTe quantum dots (QDs)
in aqueous system and its analytical application based on
the ECL energy transfer to analytes. The CdTe QDs were
modified with mercaptopropionic acid to obtain water-soluble QDs and stable and intensive anodic ECL emission with a peak value at +1.17 V (vs Ag/AgCl) in pH 9.3
PBS at an indium tin oxide (ITO) electrode. The ECL
emission was demonstrated to involve the participation
of superoxide ion produced at the ITO surface, which
could inject an electron into the 1Se quantum-confined
orbital of CdTe to form QDs anions. The collision between
these anions and the oxidation products of QDs led to the
formation of the excited state of QDs and ECL emission.
The ECL energy transfer from the excited CdTe QDs to
quencher produced a novel methodology for detection of
catechol derivatives. Using dopamine and L-adrenalin as
model analytes, this ECL method showed wide linear
ranges from 50 nM to 5 
M and 80 nM to 30 M for these
species. Both ascorbic acid and uric acid, which are
common interferences, did not interfere with the detection
of catechol derivatives in practical biological samples.
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