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Electrochemiluminescent pH sensor measured by the emission potential of TiO 2 nanocrystals and its biosensing application
Author(s) -
Liu Xuan,
Wang Nianyue,
Zhao Wei,
Jiang Hui
Publication year - 2015
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.2697
Subject(s) - biosensor , chemistry , anatase , indium tin oxide , urease , inorganic chemistry , nanocrystal , electrochemiluminescence , electrode , nanotechnology , analytical chemistry (journal) , catalysis , materials science , urea , chromatography , biochemistry , organic chemistry , photocatalysis
This work reports for the first time a potential‐based nano‐electrochemiluminescent (ECL) pH sensor, using anatase TiO 2 nanocrystals (NCs) as the ECL probe. The first ECL peak potential of the TiO 2 NCs shifted negatively with increasing pH, showing a linear range from −0.47 V (vs Ag/AgCl) at pH 3 to −1.06 V at pH 10. This phenomenon was attributed to the absorption of ‘potential‐determining ions’ of OH − on the surface of TiO 2 NCs, leading to larger impedance of the electron injection. Other common ‘potential‐determining ions’, such as phosphate, induced a slight potential shift of 0.03 V at a concentration of 0.1 M. Using urease as an enzyme model, a urea biosensor was developed by the simultaneous modification of urease and TiO 2 NCs on indium–tin oxide (ITO) electrodes. The biosensor, measured on the basis of the pH increase caused by the enzyme catalysis reaction, had a linear range of 0.01–2.0 mM, with a potential shift of 0.175 V. The as‐prepared pH sensor, which has simple construction procedures and acceptable sensitivity and selectivity, may provide new avenues for the construction of ECL bioanalytical methodologies. Copyright © 2014 John Wiley & Sons, Ltd.