Characterization, Direct Electrochemistry, and Amperometric Biosensing of Graphene by Noncovalent Functionalization with Picket-Fence Porphyrin

Authors

  • Wenwen Tu,

    1. MOE Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-8359-3593
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  • Dr. Jianping Lei,

    1. MOE Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-8359-3593
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  • Siyuan Zhang,

    1. MOE Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-8359-3593
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  • Prof. Huangxian Ju

    1. MOE Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-8359-3593
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Abstract

Reduced graphene oxide (RGO) was prepared and functionalized with picket-fence porphyrin, 5,10,15,20-tetrakis [αααα-2-trismethylammoniomethylphenyl] porphyrin iron(III) pentachloride (FeTMAPP), through π–π interactions. The resulting nanocomposite was characterized by atomic force microscopy (AFM); transmission electron microscopy (TEM); contact angle measurements; and fluorescence, Raman, and UV/Vis absorption spectroscopy. On account of the introduction of positively charged FeTMAPP, the functionalized RGO showed good dispersion in aqueous solution. The RGO could greatly accelerate the electron transfer of FeTMAPP to produce a well-defined redox couple of FeIII/FeII at −0.291 and −0.314 V. Due to the synergic effect between RGO and the porphyrin, the nanocomposite showed excellent electrocatalytic activity toward the reduction of chlorite, thus leading to highly sensitive amperometric biosensing at low applied potential. The biosensor for chlorite showed a linear range from 5.0×10−8 to 1.2×10−4 mol L−1 with a detection limit of 2.4×10−8 mol L−1 at a signal-to-noise ratio of 3. The picket-fence porphyrin could serve as an efficient species to functionalize graphene for electronic and optical applications.

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