Copolypeptide-doped polyaniline nanofibers for electrochemical detection of ultratrace trinitrotoluene.
This paper demonstrates a new electrochemical method for the detection of ultratrace amount of 2,4,6-trinitrotoluene (TNT) with synthetic copolypeptide-doped polyaniline nanofibers. The copolypeptide, comprising of glutamic acid (Glu) and lysine (Lys) units, is in situ doped into polyaniline through the protonation of the imine nitrogen atoms of polyaniline by the free carboxylic groups of Glu segments, resulting in the formation of polyaniline nanofibers of emeraldine salt. The free amino groups of Lys segments at the surface of nanofibers provide the receptor sites of TNT through the formation of charge-transfer complex between the electron-rich amino groups and the electron-deficient aromatic rings. Adsorptive stripping voltammetry results demonstrate that the poly(Glu-Lys)-doped nanofibers confined onto glassy carbon electrodes exhibit a remarkable enriching effect and thus sensitive electrochemical response to TNT with a linear dynamic range of 0.5-10 microM and a detection limit down to 100 nM. Moreover, other kinds of nitro compounds show different redox behaviors from TNT at the doped nanofibers, and thus do not interfere with the electrochemical detection of TNT. This study essentially offers a new and simple method for electrochemical detection of ultratrace TNT.
Wang
Feng
F
Key Laboratory of Biomimetic Sensing & Advanced Robot Technology, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
Wang
Wenbo
W
Liu
Bianhua
B
Wang
Zhenyang
Z
Zhang
Zhongping
Z
D000814:Aniline Compounds; D055664:Electrochemical Techniques / Q000379:methods* / Q000592:standards; D004566:Electrodes / Q000592:standards; D018698:Glutamic Acid; D008239:Lysine; D049329:Nanostructures / Q000737:chemistry; D010084:Oxidation-Reduction; D010455:Peptides; D014303:Trinitrotoluene / Q000032:analysis*
D000814:Aniline Compounds; D010455:Peptides; C416807:polyaniline; D014303:Trinitrotoluene; D018698:Glutamic Acid; D008239:Lysine