Synthesis of nano-sized cyanide ion-imprinted polymer via non-covalent approach and its use for the fabrication of a CN−-selective carbon nanotube impregnated carbon paste electrode

• The nano-sized CN−-imprinted polymer was synthesized by the non-covalent approach.
• The kind and amount of monomers, cross-linker and solvent were definitive factors.
• Cyanide imprinted polymer was used as CN− ionophore in a carbon paste electrode.
• Nernstian slope and DL of the electrode were 55.3 mV and 8 µM, respectively.
• CNT loading in the electrode decreased DL at the expense of loss in Nernstian slope.

Nano-sized CN−-imprinted polymer was synthesized by the copolymerization of methyl methacrylic acid (MAA), vinyl pyridine (VP) and ethylene glycol dimethacrylate in the presence of cyanide ion. The obtained polymeric nanoparticles were incorporated with carbon paste electrode (CPE) to produce a CN−-selective electrode. Functional monomer kind had crucial influence on the efficiency of the sensor. The presence of both VP and MAA in the structure of the imprinted polymer improved the sensing characteristics of the electrode. Also, the mole ratio of MAA/VP, cross-liker kind, cross-linker amount, solvent kind and amount were found to be effective factors in the electrode behavior. Presence of little amount of multi-walled carbon nanotubes (MWCNTs) in the CPE improved the detection range and response time of the electrode at the expense of small decrease in Nernstian slope. The electrode, containing CN−-imprinted polymer and MWCNTs showed a dynamic linear range of 1×10−6–1×10−1 mol L−1, Nernstian slope of 46.3±(0.6) mV and detection limit of 7.5×10−7 mol L−1; whereas, the same electrode in the absence of MWCNTs led to linear range, Nernstian slope and detection limit of 1×10−5–1×10−1 mol L−1, 55.3±(0.7) mV and 8×10−6 mol L−1, respectively. The utility of the electrodes was checked by determination of cyanide ion in some real samples.

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