Browsing by Author "Dhawale, A."

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Benzidine-based chemosensors for the selective detection of phosphate, carbonate and copper ions: Applications in water and food sample analysis and on-field detection kit
(Elsevier Inc., 2024) Chowdhary, A.; Dhawale, A.; Trivedi, D.R.
In this work, benzidine-based chemosensors were synthesized. A5R1 had a cage-like structure along with 2-OH binding sites for encapsulation of Cu2+, A5R2 was found to bind with PO43¯ and CO32¯ ion; whereas A5R3 was innocent towards any cations or anions. The LOD for A5R1 with Cu2+ was found to be 2.63 ppm. A5R2 detected PO43¯ and CO32¯ with limit of detections 4.13 ppm and 5.40 ppm respectively. The interference studies indicated that there was no other ion which could restrain the analysis. Job's Plots showcased the 1:2 binding of the receptors with the analyte ion(s). The practical applicability of the probes was demonstrated by on-field detection kit and test-strip fabrication with colour change chart. Logic gate formulation with active simulation governed by the reversibility studies envisaged the reversibility and reusability of the probe and its solicitation in making electric devices. Furthermore, spiking studies proved the application of the receptors for convenient analyte detection in real-life food and water samples. © 2024 Elsevier B.V.
Chromogenic Chemosensor for Simultaneous Detection of PO43? and CO32? Anions in Organo-Aqueous Solutions: Application in Arduino Based Electronic Color Sensor Device and Logic Gate
(John Wiley and Sons Inc, 2024) Dhawale, A.; Trivedi, D.R.
Three new chromogenic receptors have been synthesized with the primary objective of facilitating the selective recognition of PO43?and CO32? ions in an organo-aqueous medium. R1 and R2 exhibit an extraordinary detection limit aligning with both EPA and WHO guidelines. R1 shows LOD of 0.135 ppm for PO43? and 0.175 ppm for CO32?, while R2 sets forth a LOD of 0.427 ppm for PO43? and 0.729 ppm for CO32?. The binding mechanism involves intramolecular charge transfer (ICT) band are substantiated by comprehensive studies that include UV-Vis titration, 1H-NMR titration, DFT studies and electrochemical studies. Chemosensors were employed in the formulation of logic gate, the fabrication of a paper strip test kit and its application in RGB color sensor device. © 2024 Wiley-VCH GmbH.
Multifunctional Chemosensors for the Simultaneous Detection of Copper and Mercury Ions: Applications in Test Strip Fabrication, Spiking Studies, and Logic Gate Formulation
(American Chemical Society, 2025) Dhawale, A.; Trivedi, D.R.
This study reports the successful synthesis of three new benzidine-based chemosensors (CRBD-1, CRBD-2, and CRBD-3). Among these, CRBD-1 and CRBD-2 exhibited exceptional selectivity and ultrafast response toward Cu2+ and Hg2+ ions, evident by a distinct naked-eye color change. The sensors demonstrated remarkable stability across a broad pH range and achieved low detection limits in the ppm range. CRBD-1 displayed a high binding constant for Cu2+ (2.42 × 108) and Hg2+ (1.45 × 107). Notably, the limit of detection (LOD) for Cu2+ (0.953 ppm) and Hg2+ (0.003 ppm) was significantly lower than the established safety thresholds set by WHO and ESEPA. The mechanism of Cu2+ sensing, involving intramolecular charge transfer (ICT), was thoroughly validated using UV-vis spectroscopy, 1H NMR, cyclic voltammetry, DFT, and Job’s plot analysis. Furthermore, reversibility studies enabled the development of logic gate operations for potential future applications. The functionality of the sensors was successfully evaluated in real-world samples like vegetable juice and water, as well as the potential of CRBD-2 as test strips for convenient, rapid, qualitative, quantitative, and naked-eye colorimetric detection of Cu2+ and Hg2+ in aqueous environments. © 2025 The Authors. Published by American Chemical Society.
Rational design of an isatin-based colorimetric and solvatochromic receptor for carbonate ions and its application in molecular-scale logic gates & memory units
(Elsevier B.V., 2025) Akhil Kumar, M.M.; Dhawale, A.; Trivedi, D.R.
A simple and highly sensitive isatin-based colorimetric sensor ISAT 3(a-d) was synthesized through a single-step reaction. The as-prepared receptor ISAT 3b with carbonate ions (CO32? ions) shows a significant red shift in the UV–visible absorption spectra and a visible color change from pale yellow to pink. Also, the receptor ISAT 3b shows unique solvatochromic behavior with CO32? ions in different aprotic solvents and solvent compositions. Moreover, the receptor's pink coloration (absorption maxima at 544 nm) with CO32? ions could be reversible by adding HSO4? ions (attain initial pale-yellow color, absorption maxima at 425 nm), which can be repeatable. The observed color changes with spectral shift and reversibility of the receptor with CO32? ions and HSO4? ions provide “ON-OFF” switching for applying molecular logic gates. Receptors exhibited properties, such as reversibility and repeatability, benefit the design of a molecular-scale sequential memory unit with a display of “Writing-Reading-Erasing-Reading”. The real sample analysis was also carried out to prove the practical applicability of receptor (ISAT 3b) for detecting CO32? ions. © 2024 Elsevier B.V.