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Amperometric L ‐cysteine Sensor Using a Gold Electrode Modified with Thiolated Catechol
Author(s) -
Xu Haitao,
Li Chaorong,
Song Dongcheng,
Xu Xiaolin,
Zhao Yan,
Liu Xiaoying,
Su Zhaohong
Publication year - 2017
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.201700162
Subject(s) - amperometry , catechol , chemistry , quartz crystal microbalance , thiol , cyclic voltammetry , cysteine , electrode , detection limit , raman spectroscopy , redox , moiety , biosensor , inorganic chemistry , electrochemistry , nuclear chemistry , chromatography , organic chemistry , adsorption , biochemistry , physics , optics , enzyme
A thiolated catechol (CA) consisting of 1,6‐Hexanedithiol (HDT) and CA was modified on a gold (Au) electrode to obtain an amperometric L ‐cysteine sensor with detection limit of 60.6 nM. The preparation of thiolated CA was conducted via a thiol addition between HDT and electro‐oxidized CA (EOCA). Briefly, the thiol addition reaction was accomplished by potential cycling of HDT/Au electrode in 0.1 M phosphate buffer (PB, pH 7.2) containing CA, and an EOCA‐HDT/Au electrode was produced. The obtained EOCA‐HDT/Au electrode exhibits a pair of well‐defined redox peaks (at 0.22/0.10 V) of o ‐quinone moiety, which effectively mediates the oxidation of L ‐cysteine in a 0.1 M PB (pH 7.2), with an over‐potential decrease by ca. 0.12 V (versus bare Au electrode). Electrochemical quartz crystal microbalance, cyclic voltammetry and surface‐enhanced Raman spectra were used to study relevant processes and/or film properties. The amperometric L ‐cysteine sensor has good anti‐interferent ability and reproducibility. It also has acceptable recovery for detection of L ‐cysteine in urine samples.