Carboxymethylagarose-AuNPs generated through green route for selective detection of Hg2+ in aqueous medium with a blue shift

Synthesis of Calixarene-Capped Silver Nanoparticles for Colorimetric and Amperometric Detection of Mercury (HgII, Hg0)

“…For the same reason, the added Hg 2+ could not interact through the free upper rim of the calixarene moieties forming network structure, resulting in aggregation of nanoparticles. It is also documented that metal-induced aggregation is expected to cause shift in SPR band with color change of the solution or a new SPR band is expected to appear; 22 however, none of them is actually observed in this case. On the other hand, as the Hg 2+ can form strong complex with the sulfur atom of the thiophene moiety, it can take away the calixarene molecules from the surface of the nanoparticles by complexation leaving nanoparticles with bare surface, which can aggregate and/or interact with free Hg 2+ ions forming Ag–Hg amalgam.…”

“…In the recent era, different kinds of nanomaterials are used for sensing of metal ions and molecules using colorimetric and fluorimetric techniques. − Among various alternative methods for detection of metal ions, colorimetric technique of sensing is one of the most promising methods of detection and it has gained considerable interest due to its simple operation. , In the area of colorimetric sensing, the use of metal nanoparticles as sensing material is growing rapidly for the detection of various metal ions. − This method has attracted attention because of their extremely high visible-region extinction coefficients (∼10 9 M –1 cm –1 ), which is several orders of magnitude higher than that of organic dyes . Surface plasmon resonance (SPR) of the metal nanoparticles exhibits intense color, which is highly sensitive toward its size, shape, and interparticle distances. , Interaction of these nanoparticles with analytes causes aggregation and/or change in size, shape, interparticle networking pattern, etc., resulting in changes in SPR absorption band and color of the solution, which is easily detectable by the naked eye even at low concentration. − Because of this unique property and also due to their simple and rapid action with high selectivity and sensitivity, the use of nanoparticles as colorimetric sensing material has become an emerging area of research.…”

Sensitive Colorimetric Hg2+ Detection via Amalgamation-Mediated Shape Transition of Gold Nanostars

“…All of the results suggest that amalgamation can lead to shape-evolution of nanoparticle and nanoalloy formation, altering their localized surface plasmonic resonance. Accordingly, several selective assays toward Hg 2+ ion detection using gold nanoparticles (Qi et al, 2012 ; Chaudhary et al, 2015 ; Park et al, 2016 ) and gold nanorods (Jin and Han, 2014 ; Schopf et al, 2017 ) have been developed based on nanoalloy formation. But, the sensitivity is not satisfied for real sample testings.…”

Graphene Oxide Reduction Activity of Seaweed Polymer Derivative:Efficient Bio-Based Alternative

“…Reduced graphene oxide can be obtained using several reducing agents such as hydrazine, NaBH 4 [12][13][14] . Recently, we have successfully tested seaweed polysaccharide agarose derivatives for the preparation of eco-friendly mercury sensor, self-healing and stretchable materials [15][16][17][18] . Till date, there is no report on the reduction of GO using agarose derivatives.…”