Selective interaction between phytomediated anionic silver nanoparticles and mercury leading to amalgam formation enables highly sensitive, colorimetric and memristor-based detection of mercury

Abstract

presently, nanotechnology is being foreseen to play an important role in developing analytical assays for the detection of pollutants like mercury (Hg 2+ ). in this study, Kokum fruit mediated silver nanoparticles (AgNPs) were differentially centrifuged to prepare anionic, monodispersed AgNPs to develop a highly sensitive, colorimetric and memristor-based assay for detection of Hg 2+ in water samples. the investigation of the highly selective reaction between Agnps and Hg 2+ using HAADf-SteM images and eDS spectrum indicated the amalgam formation through etching and under potential deposition which resulted in a visible color change from brown to colorless, change in SpR intensity and also change in memristive switching like property of Agnps. the developed colorimetric assay detected Hg 2+ with a limit of detection (LOD) of 6.2 ppb and limit of quantification (LOQ) of 18.9 ppb and, quantitatively recovered Hg 2+ with good accuracy and precision (RSD < 2%). Further, the test of memristive switching like property of AgNPs demonstrated frequency-dependent shrinkage of i-V hysteresis loop indicating memristive switching like property. the test of the sensitivity of Hg 2+ detection was estimated to be 8.7 ppb as the LOD and 26.4 ppb as LOQ. Like the colorimetric assay, the memristor-based assay also recovered Hg 2+ with good accuracy and precision.Residues of mercury (Hg) based organic and inorganic compounds that are used as pesticide or fungicides in agriculture practices can accumulate in aquatic organisms. The residual toxicity of Hg can lead to serious health issues in animals and humans who consume such contaminated aquatic organisms 1 . Coal-burning power plants are the main sources of the pollution of Hg. In addition, other sources from natural and human activities are also known to contribute to Hg pollution 2,3 . It is known that water dissolved ions of mercury (Hg 2+ ) are the most common and stable form of Hg for which point of care detection is necessary to detect and monitor the Hg 2+ levels. Devising selective and sensitive methods for point of care detection of Hg 2+ from clinical diagnostics, household, environment, and industrial waste samples is expected to greatly help protect public health and the environment 4 .Recently, nanotechnology has been foreseen to play a significant and important role in developing the lab-on-chip devices for the detection of environmental pollutants. Metal nanoparticles (NPs) such a silver NPs (AgNPs) and gold NPs (AuNPs) have been demonstrated for their use in heavy metal sensing application 4-8 . Recently, differently synthesized and modified AgNPs and AuNPs were demonstrated for their use in Hg 2+ detection 9-12 . It is noteworthy that all these studies reported the need for functionalization and formation of the complex of a ligand with Hg 2+ for detection. The procedures of surface functionalization of nanomaterials (NMs) are www.nature.com/scientificreports www.nature.com/scientificreports/ somewhat tedious, prone to contamination, require sophisticated instrumen...

Highly sensitive and selective colorimetric detection of dual metal ions (Hg2+and Sn2+) in water: an eco-friendly approach

“…All these calculations were performed using the GAUSSIAN 16 suite of programs. 62 Preparation of water samples Pradesh. Suitable amounts of 1 mM standard solutions of Hg 2+ , Sn 2+ and other metal ions were added to these collected samples, mixed thoroughly and ltered.…”

On the Suitable Choice of Metal for HgTe Nanocrystal-Based Photodiode: To Amalgam or Not to Amalgam

“…Although the use of Ag nanoparticles is an established method to capture solvated Hg 2+ ions, − the observed transformation is somehow unexpected at such low temperatures and while the two materials cannot interpenetrate each other. We thus further investigated how the electronic properties of the system get affected using X-ray photoemission spectroscopy (Figure and S4–S6).…”

“…Cation exchange is a well-known process occurring over NCs. Exposure of NCs to cations can lead to an exchange procedure in which the native cations are replaced by those in solution while the anion lattice remains mostly unaffected. − The procedure was initially developed for a full exchange but rapidly appeared to be more general and has been used to form heterostructures , or as a strategy to achieve doping. , The process is nevertheless not limited to nanomaterials and has actually even been used before as a strategy to achieve alloying and doping in bulk II–VI semiconductors. For example, Zn doping can be conducted on HgCdTe , alloys.…”

Silver Nanoparticles as a selective probe for Mercury Ions: A Review

“…63, No. 7, pp: 2774-2782 2778 through the so-called under-potential deposition (UPD), which leads to formation of amalgam [53,54], .…”