Detection of 2,4-dichlorophenoxyacetic acid in water sample by organosilane based silica nanocomposites

A fluorometric sensor for Tin(II) detection using Azomethine-Triazole organosilane: Turn-off mechanism, antioxidant activity and molecular docking insights

The need for metal ion sensors is increasing daily due to the harmful impact of metal ions on human health, the environment, and the aquatic ecosystem. The present study highlights synthesizing an azomethine functionalized triazole allied organosilane (5a) probe as a turn-off fluorometric sensor for Sn(II) recognition with high anti-interference even when the other metal ions are present. The probe (5a) offers a detection limit of up to 6.4 × 10-10 M which is much lesser than the WHO acceptable limit (2 µg/L) of Sn(II) in drinking water. The fluorometric and absorbance-based UV-visible spectroscopy method is used for this analysis due to their ease of sample preparation, low cost, quick analysis, high sensitivity and selectivity, and less time-consuming nature. The real sample analysis (recovery % more than 97) results of the probe (5a) prove that it can detect the Sn(II) in different water samples increasing its practical applicability. The biological activities of the presently synthesized compounds were also studied providing valuable insights into their biological potential. Probe (5a) showed effective antioxidant potential. Bacterial domain inhibition by Probe (5a) was also analyzed using molecular docking, which showed good inhibitory activity by the probe (5a).

Chalcone derived bis-organosilane and its magnetic nanoparticles: Unveiling precision in selective Cu(II) ion detection and elucidating biocompatibility

The escalating concern regarding the adverse effects of metal ion toxicity on both human health and environmental ecosystems necessitates the development of efficient detection methodologies. This study presents a focused investigation on the selective and sensitive detection of Cu(II) ions employing hybrid magnetic nanoparticles derived from chalcone-based bis-organosilane. These nanoparticles exhibit a notably low detection limit in the nano-scale range, rendering the sensor highly sensitive to Copper(II) ion detection while maintaining robust anti-interference capabilities, even in the presence of diverse metal ions. Real sample analysis confirms the sensor's efficacy in detecting Cu(II) ions below WHO-prescribed levels. Computational analyses reveal molecular interactions and biological activities, including potent antibacterial and antioxidant properties, suggesting promising applications. Furthermore, the biological effectiveness of chalcone-derived bis-organosilane is investigated, unveiling notable antibacterial efficacy and also exhibiting potential as a scavenger of free radicals, indicating promising applications in both antibacterial and antioxidant domains.

Efficiently catalytic ozonation of 2,4-dichlorophenoxyacetic acid by natural ferrihydrite: A pH dependent and surface -OH group involved reaction mechanism

The heterogeneous catalytic ozonation with natural iron oxides has been proven to be a powerful technology for the removal of recalcitrant organics in water due to the involvement of reactive oxygen species. However, little information can be obtained about the performance of Ferrihydrite in catalytic ozonation especially the relavant reaction mechanism. In this study, Ferrihydrite was synthesized via a simple precipitation method and 2,4-Dichlorophenoxyacetic acid (2,4-D) degradation was used to evaluate its catalytic ozonation performance. Compared with sole ozonation, Ferrihydrite had an excellent activity in catalytic ozonation and 2,4-D was always efficiently degraded (>90%) at a wide pH range (3.0-8.0). Electron spin resonance (ESR) and radical scavenging tests proved that •OH and O2•- were the dominant reactive oxygen species (ROS) in 2,4-D degradation (92.33% vs. 77.4% in ozone alone) and mineralization (63% vs. 16.2% in ozone alone). Based on a series of characterizations, Ferrihydrite processed a higher BET area and surface -OH groups than other iron oxides such as FeOOH, Fe2O3 and Fe3O4. The efficiently exposed surface -OH group with a high density was the reactive centers for the generation of ROS. Importantly, pHPZC of Ferrihydrite (6.3) and pKa of 2,4-D (2.73) induced a pH-dependent 2,4-D removal patterns (surface reaction at pH < 6.3 and reaction in bulk solution at pH > 6.3) were proposed via the electrostatic attraction or repulsion between the hydrogenated/hydroxylated surface of Ferrihydrite and negative charged 2,4-D.

One-Pot Preparation of Ratiometric Fluorescent Molecularly Imprinted Polymer Nanosensor for Sensitive and Selective Detection of 2,4-Dichlorophenoxyacetic Acid

The development of fluorescent molecular imprinting sensors for direct, rapid, and sensitive detection of small organic molecules in aqueous systems has always presented a significant challenge in the field of detection. In this study, we successfully prepared a hydrophilic colloidal molecular imprinted polymer (MIP) with 2,4-dichlorophenoxyacetic acid (2,4-D) using a one-pot approach that incorporated polyglycerol methacrylate (PGMMA-TTC), a hydrophilic macromolecular chain transfer agent, to mediate reversible addition-fragmentation chain transfer precipitation polymerization (RAFTPP). To simplify the polymerization process while achieving ratiometric fluorescence detection, red fluorescent CdTe quantum dots (QDs) and green fluorescent nitrobenzodiazole (NBD) were introduced as fluorophores (with NBD serving as an enhancer to the template and QDs being inert). This strategy effectively eliminated background noise and significantly improved detection accuracy. Uniform-sized MIP microspheres with high surface hydrophilicity and incorporated ratiometric fluorescent labels were successfully synthesized. In aqueous systems, the hydrophilic ratio fluorescent MIP exhibited a linear response range from 0 to 25 μM for the template molecule 2,4-D with a detection limit of 0.13 μM. These results demonstrate that the ratiometric fluorescent MIP possesses excellent recognition characteristics and selectivity towards 2,4-D, thus, making it suitable for selective detection of trace amounts of pesticide 2,4-D in aqueous systems.

Assessing the greenification potential of cyclodextrin-based molecularly imprinted polymers for pesticides detection

Cyclodextrins, with their unparalleled attributes of eco-friendliness, natural abundance, versatile utility, and facile functionalization, make a paramount contribution to the field of molecular imprinting. Leveraging the unique properties of cyclodextrins in molecularly imprinted polymers synthesis has revolutionized the performance of molecularly imprinted polymers, resulting in enhanced adsorption selectivity, capacity, and rapid extraction of pesticides, while also circumventing conventional limitations. As the concern for food quality and safety continues to grow, the need for standard analytical methods to detect pesticides in food and environmental samples has become paramount. Cyclodextrins, being non-toxic and biodegradable, present an attractive option for greener reagents in imprinting polymers that can also ensure environmental safety post-application. This review provides a comprehensive summary of the significance of cyclodextrins in molecular imprinting for pesticide detection in food and environmental samples. The recent advancements in the synthesis and application of molecularly imprinted polymers using cyclodextrins have been critically analyzed. Furthermore, the current limitations have been meticulously examined, and potential opportunities for greenification with cyclodextrin applications in this field have been discussed. By harnessing the advantages of cyclodextrins in molecular imprinting, it is possible to develop highly selective and efficient methods for detecting pesticides in food and environmental samples while also addressing the challenges of sustainability and environmental impact.

Bis-triazole linked organosilane based sensing platform for Cu2+ ions and insilico tyrosinase inhibitor activity

The development of a ligand for their selective and sensitive detection is required due to the widespread use of Cu²⁺ in many industrial processes and the potential threat to human health. Herein, we report a bis-triazole linked organosilane (5) derived from the Cu(I) catalyzed azide-alkyne cycloaddition reaction. The synthesized compound 5 was characterized by (¹H and ¹³C) NMR spectroscopic and mass spectrometry techniques. The UV-Visible and Fluorescence experiments of the designed compound 5 were performed with various metal ions, revealing its high selectivity and sensitivity to Cu²⁺ ions in MeOH: H₂O (8:2, v/v, pH = 7.0, PBS buffer) solution. The selective fluorescence quenching upon addition of Cu²⁺ to the compound 5 is due to Photo-induced electron transfer process (PET). The limit of detection of compound 5 to Cu²⁺ was calculated as 2.56 × 10^-6 M and 4.36 × 10^-7 M through UV-Visible and Fluorescence titration data, respectively. The possible mechanism of 1:1 binding of 5 with Cu²⁺ could be affirmed by the density functional theory (DFT). Further, it was found that compound 5 showed a reversible behavior towards Cu²⁺ ions by the accumulation of sodium salt of CH₃COO^- which can be used in the construction of molecular logic gate where Cu²⁺ and CH₃COO^- are considered as inputs and the absorbance at 260 nm as output. Moreover, the molecular docking studies provide useful information about compound 5's interaction with the tyrosinase enzyme (PDB ID- 2Y9X).