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Optically Transparent Electrodes Modified with Sulfide Ion‐Covered CdS Quantum Dots for Sensitive Photoelectrochemical Detection of Sulfhydryl‐Containing Compounds
Author(s) -
Zhang Lin,
Hao Yuanqiang,
Wang Xiaoying,
Long Yunfei,
Ramos Angela,
Jiang Dianlu,
Ma Xiaohua,
Lin Qinlu,
Zhou Feimeng
Publication year - 2015
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201500078
Subject(s) - quantum dot , detection limit , photocurrent , electrode , indium tin oxide , analyte , photoelectrochemistry , chemistry , inorganic chemistry , ion , indium , materials science , photochemistry , nanotechnology , optoelectronics , electrochemistry , chromatography , organic chemistry
A sensitive and selective photoelectrochemical sensor has been developed. Negatively charged, citrate‐capped CdS quantum dots (QDs) are assembled layer‐by‐layer onto indium tin oxide (ITO) electrodes precoated with positively charged poly(diallyldimethylammonium chloride). By exposing the modified photoelectrochemical electrodes to a Na 2 S solution, QDs can be covered with excess S 2− ions. The weakly bound S 2− ions are easily replaceable with a sulphydryl‐containing analyte, and the photocurrent decrease is proportional to the analyte concentration. The detection limit is 0.4 nM for cysteine with a linear range of 1.0–100.0 nM. The level of cysteine in human serum samples has been quantified.