A rhodamine based chemosensor for solvent dependent chromogenic sensing of cobalt (II) and copper (II) ions with good selectivity and sensitivity: Synthesis, filter paper test strip, DFT calculations and cytotoxicity

Wei Chuen Chan, Hazwani Mat Saad, Kae Shin Sim, Vannajan Sanghiran Lee, Chee Wei Ang, Keng Yoon Yeong, Kong Wai Tan

    Research output: Contribution to journalArticleResearchpeer-review


    A new chemosensor 1 was synthesized by reacting rhodamine B hydrazide and 2,3,4-trihydroxybenzaldehyde, which was then characterized by spectroscopic techniques and single crystal X-ray crystallography. Sensor 1 has the ability to sense Co2+/Cu2+ ions by “naked-eye” with an apparent colour change from colourless to pink in different solvent system, MeCN and DMF respectively. Furthermore, it can selectively detect Co2+/Cu2+ among wide range of different metal ions, and it exhibits low detection limit of 4.425 × 10−8 M and 1.398 × 10−7 M respectively. Binding mode of the two complexes were determined to be 1:1 stoichiometry for Co2+ complex and 1:2 stoichiometry for Cu2+ complex through Job's plot, IR spectroscopy, mass spectrometry and 1H NMR spectroscopy. Moreover, reversibility of the sensor 1 as copper (II) ion detector was determined by using EDTA and the results showed that sensor 1 can be reused for at least 6 cycles. Other than that, a low cost chemosensor test strips were fabricated for the convenient “naked-eye” detection of Co2+ and Cu2+ in pure aqueous media. The MTT assay was conducted in order to determine the cytotoxicity of sensor 1 towards human cell lines.

    Original languageEnglish
    Article number120099
    Number of pages14
    JournalSpectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
    Publication statusPublished - 5 Dec 2021


    • Chemosensor
    • Co
    • Cu
    • Rhodamine
    • Solvent dependent sensing
    • “Naked-eye” detection

    Cite this