Applicability of a synthesized melamine based covalent organic framework as a novel ionophore for the potentiometric determination of mercury (II): Computational and experimental studies

[Display omitted] •The applicability of a COF as an ionophore was studied for the first time.•Schiff base network1 (SNW1) was synthesized and characterized with various methods.•DFT computations were employed for investigating Hg2+complexation with SNW1.•SNW1 was used as an ionophore for the construction of a Hg2+ selective electrode.•Hg2+ was detected at 80 nmol/L (∼16.05 ppb) level. In this research, the complexation of a recently synthesized covalent organic framework (schiff base network1) with 10 different cations was investigated by QTAIM (quantum theory of atoms in molecules) computations. The theoretical results showed the schiff base network1 interactions with Hg2+ is considerably stronger than other cations and it can be used as an selective ionophore for the development of a potentiometric sensor to determination of Hg2+. Therefore, a Hg2+ selective PVC membrane coated graphite electrode was developed based on schiff base network1. The best response was observed form the membrane composition of PVC (32 %), Nitrobenzene (60 %), sodium tetraphenylborate (2 %), and schiff base network1 (6 %). The designed sensor showed an excellent Nernstian response to Mercury (II) (29.8 mV. Decade−1) over a wide activity range from 1 × 10−7 to 5 × 10−3 and the detection limit of the proposed potentiometric sensor was 8 × 10−8. The effect of different interfering species on the potentiometric response of the suggested electrode was scrutinized by matched potential method (MPM) and no interference was observed. The performance of the developed electrode in partially non-aqueous mediums was also checked out and the obtained results showed the electrode can also be utilized in systems containing %20 organic solvents (ethanol and acetone). The response time and lifespan of the electrode were