posted on 2024-02-28, 00:33authored byRamamoorthi Tamizhselvi, Rangaswamy Bhaskar, Somanahalli Kalleshappa Ashok Kumar, Sonaimuthu Mohandoss, Yong Rok Lee, Ayyakannu Arumugam Napoleon
A newly synthesized
Schiff’s base 2-(2-([2,2′-bithiophen]-5-ylmethylene)hydrazinyl)benzothiazole
(BT) was obtained from the condensation reaction between
2-hydrazinobenzothiazole and 2,2-bithiophene-5-carboxaldehyde. The
prepared probe BT was subjected to a confirmation of
the structural arrangement through NMR, FTIR, ESI-HRMS, and single-crystal
XRD spectral analysis. The BT colorimetric sensor showed
selectivity and sensitivity toward the cyanide (CN–) ion over other common anions such as ClO4–, Cl–, Br–, F–, I–, NO2–, OH–, HSO4–, and H2PO4– in a partial aqueous system CH3CN/H2O (8:2, v/v). The probe BT detects
CN– with the lowest detection range as low as 1.33
× 10–8 M (3.59 ppm); in comparison to that
given by WHO guidelines, it is significantly lower. The stoichiometric
interaction between the probe BT and analyte CN– was found to be 1:1 (BT/CN–) binding mode using
Jobs plot, and further association binding affinity was calculated
to be 6.64 × 10–3 M–1. Additionally,
these results were further supported by the FTIR and DFT calculations,
as well as the 1H NMR titration analysis, which complemented
the binding data. The sensor probe BT was successfully
employed in a cotton swab test kit approach and also in smartphone-assisted
applications for the determination of CN– ions.
Finally, the outstanding sensing properties of probe BT aided the quantitative detection of CN– ions,
and it could be further applied to a variety of food samples, including
apple seeds, sprouting potatoes, and cassava.