scholarly journals pH Dependence on Colorimetric Detection of Hg2+ by Histidine-Functionalized Gold Nanoparticles

2020 ◽  
Vol 20 (4) ◽  
pp. 941
Author(s):  
Dewi Eviane ◽  
Dwi Siswanta ◽  
Sri Juari Santosa

In this study, we successfully developed gold nanoparticles capped with histidine (His-AuNPs) for Hg2+ detection using trisodium citrate as the reducing agent. The optimum pH for the detection of Hg2+ by His-AuNPs was 12. The addition of Hg2+ to the His-AuNPs caused the color change from red to black-blue, which is readily detectable by the naked eye. This color change is followed by a decrease in the intensity of the primary Surface Plasmon Resonance (SPR) peak at a wavelength (λ) of 525 nm and an increase in the secondary peak at λ = 650 nm. His-AuNPs effectively detected Hg2+ with limits of detection and quantitation of 1.77 µM and 5.89 µM, respectively. His-AuNPs exhibited good performance for the detection of Hg2+ in waste water collected from a steel industrial facility in Banten Province, with a recovery and a percent relative standard deviation of 115% and 1.02%, respectively.

2019 ◽  
Vol 11 (29) ◽  
pp. 3706-3713 ◽  
Author(s):  
Mohammed Awad Abedalwafa ◽  
Yan Li ◽  
Chunfang Ni ◽  
Gang Yang ◽  
Lu Wang

Non-enzymatic colorimetric sensor strip for detection of metronidazole (MTZ) was designed and constructed, with high sensitivity and selectivity. Which can be used for naked-eye detection of MTZ with a visible color change from pink to purple.


2013 ◽  
Vol 790 ◽  
pp. 619-622
Author(s):  
Chong Jin ◽  
Hui Min Zhao ◽  
Meng Liu ◽  
Jun Ping Tian ◽  
Xie Quan

A simple, fast and reliable colorimetric method for melamine detection based on gold nanoparticles (AuNPs) and poly-thymine (poly-T) is reported. Poly-T strands attract AuNPs through static electricity and keep them stable against aggregation in the presence of NaCl. The affinity between melamine and poly-T, hydrogen bond, frees AuNP from the protection provided by poly-T and thus makes AuNPs aggregate in the presence of NaCl. The color change of AuNPs from wine red to blue can be observed immediately by the naked eye during the aggregation process, and can be accurately recorded with the help of a UV/vis spetrophotometer within 5 minutes. The limit of detection (LOD) of melamine in pure water is 0.146 μmol/L with a linear range from 0.2×10-7 mol/L to 10.0×10-7 mol/L. In fresh milk and milk powder, the LOD is respectively as low as 2.37 μmol/L and 5.36 μmol/L.


Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 302 ◽  
Author(s):  
Carlos Martínez-Aquino ◽  
Ana Costero ◽  
Salvador Gil ◽  
Pablo Gaviña

Gold nanoparticles functionalized with resorcinol moieties have been prepared and used for detecting formaldehyde both in solution and gas phases. The detection mechanism is based on the color change of the probe upon the aggregation of the nanoparticles induced by the polymerization of the resorcinol moieties in the presence of formaldehyde. A limit of detection of 0.5 ppm in solution has been determined. The probe can be deployed for the detection of formaldehyde emissions from composite wood boards.


The Analyst ◽  
2021 ◽  
Author(s):  
Almas Shamaila Mohammed ◽  
Aniket Balapure ◽  
Mahammad Nanne Khaja ◽  
Ramakrishnan Ganesan ◽  
Jayati Ray Dutta

An Au NP based facile strategy for the rapid, early-stage, and sensitive detection of HCV RNA in clinical samples which avoids thiol tagging to the antisense oligonucleotide and expensive infrastructure is presented.


The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 3989-3995 ◽  
Author(s):  
Yuanjian Liu ◽  
Linqun Zhang ◽  
Wei Wei ◽  
Hongyu Zhao ◽  
Zhenxian Zhou ◽  
...  

A colorimetric immunosensor for IAV based on AuNPs modified with mAb is developed. This assay depends on an ordered AuNPs structure covering the virus surface and can be applied to any viral pathogen by incorporating the appropriate pathogen-specific antibody, giving the proposed method a broad prospect in clinical diagnosis applications.


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