Credentials of chromone based probe as colorimetric sensor for the detection of Cu²⁺ ion: design of test paper kit...

3-(5-Chloro-2,3-dihydrobenzo[d]thiazol-2-yl)-4H-chromen-4-one (MCF) is spectroscopically characterised (FT-IR, UV-Vis, ESI-MS, NMR) and has been used for the chromogenic selective recognition of Cu²⁺ ion in EtOH-H₂O (99:1, v/v) medium in presence of fourteen competitive ions and the limit of detection is 0.6 μM (WHO recommended the permissible limit, 20 μM). The Job's plot identifies the 1:1 M ratio of probe, MCF:Cu²⁺. The Benesi-Hildebrand equation calculates the binding constant, 4.9346 × 10⁴ M^-1 which signifies the sufficient stability of probe-analyte composite. A paper kit is designed and has been impregnated with probe. It is dried and has been used for the detection of Cu²⁺ in water. On dipping the probe kit in Cu²⁺ contaminated water with other cations develops yellowish brown color while no change is seen in absence of Cu²⁺. The biocompaitability and non-toxicity of the MCF was examined by MTT assay in MDA-MB-231 cell line. The experimental outcome depicted that the probe can be used as a potential therapeutic candidate towards TNBC treatment.