Faculty Publications

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Author: search.filters.author.Singh, A.Subject: search.filters.subject.Arsenite

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    Substituent effect on colorimetric detection of biologically and environmentally relevant anions: Insight in real-life applications
    (Elsevier B.V., 2019) Singh, A.; Girish Gowda, R.; Trivedi, D.
    A new set of chromogenic anion receptors R1-R4 have been synthesized with a different substituent, including electron withdrawing (nitro moiety in R1), conjugated group (naphthyl in R2), and electron donating (methyl in R3), respectively. The receptors R1-R4 exhibited very good sensitivity towards the F ? and AcO ? anions in the DMSO. In addition, R1 showed selectivity towards H 2 PO 4 ? ions over other tested anions. R1 especially acted as an effective sensor for sodium salts of F ? , AcO ? , AsO 2 ? , and AsO 4 2? ions in an aqueous medium due to the presence of two electron-withdrawing nitro substituents, which showed hydrogen bond donor tendency and acidity of the OH proton. This result indicates that R1 is highly capable of competing with an aqueous medium to detect anions without counter Na + ion interference. Interestingly, R1 displays solvatochromic property in the presence of AcO ? ions in different aprotic solvents. Additionally, the receptor R1 shows high binding affinity towards AcO ? ions in the buffer medium (DMSO: HEPES, 9:1 v/v), which displayed remarkable colour change from pale yellow to blue with a large ?? red shift of 170 nm. The CV studies reveal the deprotonation of the -NH proton upon interaction with the AcO ? ions. The receptor R1 is subjected to practical application to sense F ? and AsO 2 ? ions using the test strip. In addition, the receptor R1 proves itself as a potential applicant for the detection of F ? ions quantitatively in commercially available mouthwash. © 2019 Elsevier B.V.
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    Chromogenic detection of fluoride, dihydrogen phosphate, and arsenite anions based on 2,4-dinitrophenyl hydrazine receptors: spectral and electrochemical study
    (Taylor and Francis Ltd., 2021) K, N.; Singh, A.; Nityananda Shetty, A.N.; Trivedi, D.R.
    The colorimetric recognition of biologically relevant fluoride (F?), acetate (AcO?), and dihydrogen phosphate (H2PO4?) ions, and poisonous arsenite (AsO2?) ions, was devised and new receptors for these anions synthesised via the Schiff base condensation procedure. UV–visible titration, fluorescence titration, 1H-NMR titration, and cyclic voltammetry were used to explore the interactions of receptors R1–R3 with anions and possible detection mechanisms. The synthesised probes could sense inorganic fluoride, acetate, dihydrogen phosphate, and arsenite in the organo–aqueous medium (H2O/ Dimethylsulphoxide, 1:?9, v/v) and displayed a change in colour detectable to the naked eye. Out of the three synthesised receptors, receptor R1 showed better sensing ability of fluoride, acetate, dihydrogen phosphate, and arsenite ions in the organo–aqueous medium with a lower detection limit of 0.1 ppm, 0.171 ppm, 0.194 ppm, and 0.144 ppm, respectively. All three receptors formed complexes with the anions through H-bonding interaction followed by deprotonation of the NH proton. © 2022 Informa UK Limited, trading as Taylor & Francis Group.