Electrosynthesis and electrochemical characterisation of polypyrrole in 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate and 1,2-dimethylimidazolium methylsulfate. Application to the detection of copper in aqueous solutions

ABSTRACT

Electropolymerisation of pyrrole was carried out in the presence of two ionic liquids: 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate and 1,2-dimethylimidazolium methylsulfate. Electrochemical technics such as cyclic voltammetry, chronoamperometry and chronopotentiometry were used. The obtained PPy films were characterised by electrostability, electroactivity and electrochemical impedance spectroscopy. After electrosynthesis and electrocharacterisation, the PPy electrosynthesised in the presence of 1,2-dimethylimidazolium methylsulfate was applied to the detection of Cu²⁺ in aqueous solutions, using Differential Pulse Anodic Stripping Voltammetry. We obtained a detection limit of 32 mg L⁻¹ for a sensitivity of 0.02 µA cm⁻² µM⁻¹ and a linear range of 3–8 mM.

KEYWORDS:

• Electropolymerisation
• conducting polymers
• polypyrrole
• ionic liquids
• electroanalysis
• heavy metals
• copper

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the [International Science Program (ISP), University of Uppsala (Sweden) under Grant to African Network of Electroanalytical Chemists [IPICS/ANEC] and by TWAS, The World Academy of Science for the Advancement of Science in developing countries under Research Grant No. [16-499RG/CHE/AF/AC_G–FR3240293299].