Investigation of Chloride Ion–Sensing Property of Polymeric Membrane and Coated Graphite Sensors Based on Bis(furan-2-carbaldehyde-N-methylthiosemicarbazonato)nickel(II) Complex

Abstract

The bis(2-carbaldehyde-N-methylfuranthiosemicarbazonato)nickel(II) complex present in a polymeric membrane electrode (PME) and a coated graphite electrode (CGE) exhibited Nernstian slope (−58.80 mV/decade) for chloride ions with a lower detection limit of 3.98 × 10⁻⁶ M (CGE). The CGE has a wide functional pH range (1.65–5.65) and fast response time (<20 s). The proposed electrodes are highly selective for chloride ions over different secondary ions, particularly toward potential interferents Br⁻, I⁻, and SCN⁻ ions (log  = − 2.00, log  = − 0.50, and log  = −1.30). The electrodes have been used as indicator electrodes in potentiometric titrations and for the estimation of chloride content in pharmaceutical samples.

Keywords:

• Chloride ion–selective electrode
• coated graphite electrode
• nickel(II) complex
• polymeric membrane electrode
• potentiometry

Durgesh Nandni is thankful for the financial assistance from the University Grants Commission–Special Assistance Program (SAP), New Delhi, India. The authors thank Poonam Kumari for providing a sample of bis(furan-2-carbaldehyde-N-methylthiosemicarbazonato) nickel(II) complex.

Notes

^a DOA: dioctyladipate.

^b DOS: bis(2-ethylhexyl)sebacate.

^c NPOE: o-nitrophenyloctyl ether.

^d [bmim]PF₆: n-butyl-3-methyl-immidazolium hexafluorophosphate.