Fluorescent Carbon Dots: Aggregation-Induced Emission Enhancement, Application as Probe for CN and CrO, Sensing Strips and Bio-imaging Agent.

Fluorescent carbon dots (Trp-CDs) were prepared using tryptophan as precursor and were characterized on the basis of elemental analysis, powder-XRD, IR, Raman spectroscopy, C-NMR, UV-Vis, fluorescence and TEM. Trp-CDs exhibit poor fluorescence in 100% water but showed strong Aggregation Induced Emission (AIE) in ethanol and higher alcohols. The anion sensing study of Trp-CD revealed that it selectively detects CN and CrO and from fluorescence quenching titration study, quenching constant, LOD and range of detection were evaluated.

Rosmarinic Acid-Capped Silver Nanoparticles for Colorimetric Detection of CN and Redox-Modulated Surface Reaction-Aided Detection of Cr(VI) in Water.

Rosmarinic acid-capped silver nanoparticles (Ro-AgNPs) were prepared and applied as a probe for selective colorimetric detection of cyanide (CN) and chromium(VI) [Cr(VI)] under different conditions in aqueous media. The carbon atom of CN interacts with the AgNPs, and the carbon atom donates electrons from the HOMO to the vacant orbitals of the coordinatively unsaturated surface atom (Ag). After donating electrons, CN attached onto the surface of the nanoparticles becomes very reactive and interacts with dissolved oxygen and generates reactive oxygen species (ROS) such as superoxide (O ), singlet oxygen (O), and so forth.

Microwave-assisted synthesis of nitrogen-doped carbon dots using prickly pear as the carbon source and its application as a highly selective sensor for Cr(VI) and as a patterning agent.

Preparation of water-dispersible carbon dots from inexpensive natural carbon precursors and its application for purposes such as sensing, bio-imaging and patterning agents is showing growing interest in recent years. In this study, we have reported the preparation of nitrogen-doped carbon dots (N-CDs) using prickly pear as the carbon source and -xylylenediamine as the nitrogen source using a one-step microwave-assisted synthetic process. The N-CDs prepared were characterized on the basis of elemental analysis, XPS, powder-XRD, FT-IR, Raman, TEM, UV-vis and fluorescence spectroscopy.

A New Molecular Probe for Colorimetric and Fluorometric Detection and Removal of Hg and its Application as Agarose Film-Based Sensor for On-Site Monitoring.

A new molecule incorporating two units of 7-nitro-benzoxadiazole (NBD), bridged by m-xylylenediamine, was synthesized and characterized on the basis of analytical and spectroscopic techniques. The metal ion sensing property of this molecule was studied spectroscopically with a large number of metal ions. This study revealed that it can perform as a dual-channel probe for colorimetric as well as fluorometric detection of Hg.

Colorimetric dual sensor for Cu(II) and tyrosine and its application as paper strips for detection in water and human saliva as real samples.

A calix[4]arene based compound incorporating amide and morpholine moieties has been synthesized and its ion recognition property towards metal ions and application of its metal complex towards sensing of amino acids has been investigated. The synthesized compound interacts with Cu with high selectivity and sensitivity (LOD, 0.1 ppb) in aqueous media with instant color change from colorless to yellow without interference from any other metal ions used in this study.

derived biomass functionalized ZnO particles for effective removal of lead(ii), iron(iii), phosphate and arsenic(iii) from water.

Owing to the vast diversity in functional groups and cost effectiveness, biomass can be used for various applications. In the present study, biomass from () was prepared and grafted onto the surface of ZnO particles following a simple method. The functionalized ZnO particles (ZnO@) were characterized and exhibited excellent adsorption properties towards Pb (506 mg g), Fe (358 mg g) and PO (1606 mg g) and the Fe adsorbed ZnO@ adsorbs AsO (189 mg g); the metal ions and anions were analyzed by ICP and IC.

Synthesis of Calixarene-Capped Silver Nanoparticles for Colorimetric and Amperometric Detection of Mercury (Hg, Hg).

Calixarene-functionalized water dispersible silver nanoparticles have been synthesized and characterized on the basis of UV-vis, IR, X-ray diffraction, and high-resolution transmission electron microscopy analysis, and their sensing properties toward metal ions have been investigated. They selectively detect Hg and Hg in solution and vapor phases, respectively, with distinct color change. Interference study with mixture of metal ions revealed no interference from any other metal ions used in this study.

Green route for synthesis of multifunctional fluorescent carbon dots from Tulsi leaves and its application as Cr(VI) sensors, bio-imaging and patterning agents.

We report a one pot green strategy for the synthesis of carbon dots using tulsi leaves and their potential application in sensing of Cr(VI) selectively. The detection mechanism is based on the phenomenon called inner filter effect (IFE) and a good linear static quenching was observed in the range of 1.6 μM to 50 μM with a detection limit of 4.

New Route for Synthesis of Fluorescent SnO₂ Nanoparticles for Selective Sensing of Fe(III) in Aqueous Media.

A simple new route for synthesis of fluorescent SnO2 and its application as an efficient sensing material for Fe3+ in aqueous media is reported. The fluorescent SnO2 nanoparticles were obtained by oxidation of SnCl2, which when used as reducing agent for the reduction of organic nitro compounds to corresponding amino compounds in ethanol. The SnO2 nanoparticles have been characterized on the basis of powder-XRD, IR, UV-Vis, TEM, FESEM and EDX analysis and found that this material is highly fluorescent in aqueous media.

Sunlight Induced Preparation of Functionalized Gold Nanoparticles as Recyclable Colorimetric Dual Sensor for Aluminum and Fluoride in Water.

A sunlight induced simple green route has been developed for the synthesis of polyacrylate functionalized gold nanoparticles (PAA-AuNPs), in which poly(acrylic acid) functions as a reducing as well as stabilizing agent. This material has been characterized on the basis of spectroscopic and microscopic studies; it exhibited selective colorimetric detection of Al in aqueous media, and the Al induced aggregated PAA-AuNPs exhibited detection of F with sharp color change and high selectivity and sensitivity out of a large number of metal ions and anions tested. The mechanistic study revealed that, for Al, the color change is due to a shift of the SPR band because of the Al induced aggregation of PAA-AuNPs, whereas for F, the reverse color change (blue to red) with return of the SPR band to its original position is due to dispersion of aggregated PAA-AuNPs, as F removes Al from the aggregated species by complex formation.

Silver nanoparticle based highly selective and sensitive solvatochromatic sensor for colorimetric detection of 1,4-dioxane in aqueous media.

A citrate stabilised silver nanoparticle (Ci-AgNP) based solvatochromic sensor, which functions as a highly selective and sensitive colorimetric probe for 1,4-dioxane in aqueous media is reported. The surfaces of the AgNPs generate reactive oxygen species, which promote the degradation of 1,4-dioxane assembled in the vicinity of the nanoparticle surfaces through charge transfer interactions. During this process, Ag(0) is oxidised to Ag(+) and the yellow colour of the solution turns to colourless.