Functionalization of Carbon Nanotubes with Water‐Insoluble Porphyrin in Ionic Liquid: Direct Electrochemistry and Highly Sensitive Amperometric Biosensing for Trichloroacetic Acid

Abstract

A functional composite of single-walled carbon nanotubes (SWNTs) with hematin, a water-insoluble porphyrin, was first prepared in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]) ionic liquid. The novel composite in ionic liquid was characterized by scanning electron microscopy, ultraviolet absorption spectroscopy, and electrochemical impedance spectroscopy, and showed a pair of direct redox peaks of the Fe(III)/Fe(II) couple. The composite-[BMIM][PF(6)]-modified glassy carbon electrode showed excellent electrocatalytic activity toward the reduction of trichloroacetic acid (TCA) in neutral media due to the synergic effect among SWNTs, [BMIM][PF(6)], and porphyrin, which led to a highly sensitive and stable amperometric biosensor for TCA with a linear range from 9.0x10(-7) to 1.4x10(-4) M. The detection limit was 3.8x10(-7) M at a signal-to-noise ratio of 3. The TCA biosensor had good analytical performance, such as rapid response, good reproducibility, and acceptable accuracy, and could be successfully used for the detection of residual TCA in polluted water. The functional composite in ionic liquid provides a facile way to not only obtain the direct electrochemistry of water-insoluble porphyrin, but also construct novel biosensors for monitoring analytes in real environmental samples.

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

“…The picket-fence porphyrin could serve as an efficient species to functionalize graphene for electronic and optical applications. [38][39][40][41] This work used watersoluble 5,10,15,20-tetrakis [aaaa-2-trismethylammoniomethylphenyl]porphyrin ironA C H T U N G T R E N N U N G (III) pentachloride (FeTMAPP), a kind of picket-fence porphyrin with one planar side and another positively charged side, to functionalize RGO by means of p-p noncovalent interactions (Scheme 1). The obtained porphyrin/RGO nanocomposite showed good dispersion.…”

Synthesis of novel functional liquid and its application as a modifier in SBR/silica composites

“…Ionic liquid (IL), a kind of fascinating molten salt with nearly zero vapor pressure and high thermal stability [5][6][7], has demonstrated high affinity toward various kinds of solid, such as carbon nanotubes [8][9][10][11][12][13][14], silica [15][16][17] and clays [18]. Various interactions, including cation-π interaction [8][9][10][11]19], van der Waal forces [13], delocalized electron interaction [14] and hydrogen bonding [16,18] have been well acknowledged and therefore subjected to a plenty of applications [14,[16][17][18][20][21][22][23][24][25][26]. Thanks to these interactions, ILs with specific structure can be employed as possible interfacial modifiers for various filled polymer composites.…”

Biofunctionalization of Nanomaterials

“…Proteins were then immobilized through a nucleophilic substitution of NHS by the amino group of the proteins to form an amide bond. Alternatively, a direct assembly of water-insoluble porphyrin on SWNT was designed based on the p-p noncovalent interaction between porphyrin and CNTs, resulting in a novel biosensor for trichloroacetic acid [43]. The covalent attachment of bioactive molecules on CNTs is considered to be a useful tool for biological applications.…”