Fabrication of triazine based colorimetric and electrochemical sensor for the quantification of Co2+ ion

Abstract

Triazine based Schiff base was synthesized by sonochemical method and it was explored for the robust selective and sensitive determination of Co2+ by both colorimetry and electrochemical sensing. Selectivity studies were carried out with different metal ions and found that the proposed chemosensor has significant selectivity for the detection of Co2+ with the colour change from yellow to blue owing to the formation of complex with Co2+.The colorimetric sensitivity studies of BNHNTA shows maximum detection value of 0.05 µM towards the quantification of Co2+. In addition the amperometric studies exhibit selective electrochemical sensing of Co2+ by BNHNTA and the detection limit was calculated to be 0.03 µM. The HOMO-LUMO diagram clearly shows mechanism of charge transfer from ligand to metal (LMCT) between the triazine and Co2+ ion. In addition to that, Density functional theoretical (DFT) study provides the structural insights about cobalt (II) complex, which confirms the square pyramidal geometry of the formed complex. Theoretical studies confirm the formation of 1:1 receptor-metal ion complex in detecting Co2+ ion. High resolution mass spectrometry (HRMS) measurements confirm the above complex structure. Job's plot measurements also justify the same.