Ratiometric fluorescence detection of Cd2+ and Pb2+ by inner filter-based upconversion nanoparticle-dithizone nanosystem

Lanthanide ion (Ln3+)‐based upconversion sensor for quantification of food contaminants: A review

“…Though rapid detection has been achieved by the proposed sensor, higher sensitivity can also be obtained by changing the recognition elements. As Chen's study, they also detected Cd 2+ in drinking water but employed organic molecules for the specific recognition (Chen et al., 2019). Studies have shown that organic molecules exhibit higher sensitivity as a recognition element compared to enzymes, which may be due to the fact that organic molecules are more stable than enzymes and less susceptible to environmental influences.…”

“…Chen et al. (2019) have designed an IFE‐based upconversion detection system for the cadmium ion (Cd 2+ ) and lead ion (Pb 2+ ) in black tea. At the pH of 8, dithizone could complex with Cd 2+ leading to the absorption band overlap with upconversion emission peak at 546 nm, which causes the fluorescence quenches, whereas at pH of 6, the absorption band of dithizone showed a blue shift with Pb 2+ , consequently recovering the upconversion fluorescence at 657 nm.…”

Morphological Control: Properties and Applications of Metal Nanostructures

“…ese metal nanocrystals with engineered structures are used as catalysts for oxidation reactions, carbon-carbon coupling, electron transfer, hydrogenation, etc. Even certain metal nanostructures have been used in industrial-scale catalytic applications [38]. It is worth noting that the reactivity and selectivity of this type of catalyst can be controlled by the morphology of nanocrystals [35].…”

“…In general, metal/silver salt precursor is mixed with reducing agent in the presence of stabilizing agent and control the size and shape of metal nanostructures. Past research publications show that silver nitrate, as a precursor, has been abundantly used due to its cheap price and easy availability [36][37][38][39]. Various reducing agents such as sodium citrate, sodium borohydride, and alcohols are widely used to reduce metal/Ag+ ions present in solution into metal/silver atoms which combine to make aggregates and finally become nanostructures.…”

Exploring the use of upconversion nanoparticles in chemical and biological sensors: from surface modifications to point-of-care devices

“…1RFS sensors based on UCNPs have been constructed for detection and quantification of several analytes such as explosives, 172 ions such as Fe 3+ , 156 Cu 2+ , 160 Pb 2+ (ref. 158 ) and Cr 3+ , 173 rhodamine, 161 among others. 165 …”