Selective colorimetric detection of Cr(iii) and Cr(vi) using gallic acid capped gold nanoparticles

2016 ◽  
Vol 45 (20) ◽  
pp. 8347-8354 ◽  
Author(s):  
Chen Dong ◽  
Genhua Wu ◽  
Zhuqing Wang ◽  
Wenzhi Ren ◽  
Yujie Zhang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gallic Acid ◽  
Color Change ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Selective Detection

A colorimetric assay is proposed for the selective detection of Cr(iii) and Cr(vi) via the aggregation-induced color change of gallic acid capped gold nanoparticles (GA-AuNPs).

scholarly journals Enhancement of the Peroxidase-Like Activity of Iodine-Capped Gold Nanoparticles for the Colorimetric Detection of Biothiols

Biosensors ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 113 ◽  
Author(s):  
Chia-Chen Chang ◽  
Tsz-Lian Hsu ◽  
Chie-Pein Chen ◽  
Chen-Yu Chen
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Detection Limit ◽  
Enzymatic Activity ◽  
Catalytic Properties ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Synergetic Effect ◽  
Vis Spectroscopy ◽  
Wide Range

A colorimetric assay was developed for the detection of biothiols, based on the peroxidase-like activity of iodine-capped gold nanoparticles (AuNPs). These AuNPs show a synergetic effect in the form of peroxidase-mimicking activity at the interface of AuNPs, while free AuNPs and iodine alone have weak catalytic properties. Thus, iodine-capped AuNPs possess good intrinsic enzymatic activity and trigger the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB), leading to a change in color from colorless to yellow. When added to solution, biothiols, such as cysteine, strongly bind to the interface of AuNPs via gold-thiol bonds, inhibiting the catalytic activity of AuNPs, resulting in a decrease in oxidized TMB. Using this strategy, cysteine could be linearly determined, at a wide range of concentrations (0.5 to 20 μM), with a detection limit of 0.5 μM using UV-Vis spectroscopy. This method was applied for the detection of cysteine in diluted human urine.

Colorimetric Detection of Trace Arsenic(III) in Aqueous Solution Using Arsenic Aptamer and Gold Nanoparticles

2014 ◽  
Vol 67 (5) ◽  
pp. 813 ◽  
Author(s):  
Minglei Yu
Keyword(s):  
Aqueous Solution ◽  
Gold Nanoparticles ◽  
Detection Limit ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Colour Change ◽  
Colorimetric Sensing ◽  
Detection Range ◽  
Colorimetric Indicator ◽  
Blue Solution

In this study, trace arsenic(iii) (AsIII) in aqueous solution was detected by applying a classical aptamer-based gold nanoparticles colorimetric sensing strategy. An arsenic aptamer was used as a sensing probe and gold nanoparticles as a colorimetric indicator. In the absence of AsIII, the gold nanoparticles were stabilised by the arsenic aptamer and remained dispersed at high NaCl concentrations, displaying a red solution. Contrarily, in the presence of AsIII, the gold nanoparticles were prone to aggregation, owing to the formation of aptamer–AsIII complex between the arsenic aptamer and AsIII, and thus exhibited a blue solution. By monitoring the colour change, a simple and fast colorimetric assay for AsIII was established with a detection range of 1.26–200 ppb and a detection limit of 1.26 ppb. Because this colorimetric assay only involves common reagents and can be assessed visually, it holds great potential for arsenic(iii) monitoring in environment-related and other applications.

Preparation of Poly(Acrylic Acid) Crosslinked-Gold Nanoparticles for Colorimetric Detection of Analytes

2019 ◽  
Vol 950 ◽  
pp. 138-143
Author(s):  
Erindyah Retno Wikantyasning ◽  
Mutmainnah Mutmainnah ◽  
Ghiyats Ramadhan ◽  
Zakky Cholisoh ◽  
Muhammad Da'i
Keyword(s):  
Gold Nanoparticles ◽  
Herbal Medicine ◽  
Acrylic Acid ◽  
Color Change ◽  
Colorimetric Detection ◽  
Ph Responsive ◽  
Herbal Medicine Product ◽  
Responsive Polymer ◽  
Medicine Product ◽  
Poly Acrylic Acid

The aims of this study are to synthesize and characterize gold nanoparticles (AuNPs) crosslinked by pH-responsive polymer poly (acrylic acid) (PAA) and its application for detection of some analytes in herbal medicine product. In this study, a pH-responsive polymer, poly (acrylic acid) was prepared by the reversible addition-fragmentation chain transfer (RAFT) polymerization method. The polymer was then cross-linked by gold nanoparticles, which was synthesized by the Turkevich method. The response of the AuNPs-crosslinked PAA was observed by the color change from red to blue at a specific pH (4-5) and was characterized by TEM. The reversible color change was resulted from aggregation and disaggregation of the AuNPs due to the shrinking and swelling of the polymer when different pH was introduced as a stimulant. This sensor has the capability of recognizing analytes such as aspirin and tolbutamide added in the herbal medicine product at the concentration of 0.04-0.05 M.

scholarly journals Facile and One Pot Synthesis of Gold Nanoparticles Using Tetraphenylborate and Polyvinylpyrrolidone for Selective Colorimetric Detection of Mercury Ions in Aqueous Medium

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Sidhureddy Boopathi ◽  
Shanmugam Senthilkumar ◽  
Kanala Lakshminarasimha Phani
Keyword(s):  
Gold Nanoparticles ◽  
Alkaline Medium ◽  
Color Change ◽  
Colorimetric Detection ◽  
Spherical Shape ◽  
Reducing Agent ◽  
Nanoparticle Dispersion ◽  
Mercury Ions ◽  
One Pot ◽  
Resonance Band

In this work, we reported for the first time, a facile and one step synthesis of gold nanoparticles from HAuCl4, employing tetraphenylborate as the reducing agent. The synthesis is not only facile but also yields “dumb-bell-shaped”particles. This shape appears to arise from a possible emulsion of the products of oxidation/decomposition of tetraphenylborate by HAuCl4, surrounding the particle. The size and shape of the AuNPs were characterized by Transmission electron microscopy (TEM) and UV-visible Spectroscopy. Interestingly, the addition of polyvinylpyrrolidone (PVP) during the synthesis was found to enhance the stability of the nanoparticle dispersion. The particles synthesized under these conditions assume “spherical” shape with the appearance of only transverse surface plasmon resonance band. The highlight of the observations is that the gold nanoparticles synthesized using tetraphenylborate as reducing agent and PVP as stabilizer are highly stable in alkaline medium, in contrast to the synthesis wherein borohydride is used as reducing agent. The AuNPs synthesized using tetraphenylborate and PVP show their mercury sensing behavior only in the alkaline medium. The color of the nanoparticle dispersion undergoes distinct color change from pink to blue with the addition of mercury ions. They also show dramatic selectivity to mercury ions in presence of other interfering ions, Pb2+, Zn2+and Ca2+.

scholarly journals A Highly Sensitive and Selective Colorimetric Hg2+ Ion Probe Using Gold Nanoparticles Functionalized with Polyethyleneimine

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Kyung Min Kim ◽  
Yun-Sik Nam ◽  
Yeonhee Lee ◽  
Kang-Bong Lee
Keyword(s):  
Gold Nanoparticles ◽  
Secondary Ion Mass Spectrometry ◽  
Color Change ◽  
Colorimetric Assay ◽  
Tap Water ◽  
Interparticle Distance ◽  
Pond Water ◽  
Assay Method ◽  
Tuna Fish ◽  
Highly Sensitive

A highly sensitive and selective colorimetric assay for the detection of Hg2+ ions was developed using gold nanoparticles (AuNPs) conjugated with polyethyleneimine (PEI). The Hg2+ ion coordinates with PEI, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the Hg2+ ion was bound to the nitrogen atoms of the PEI in a bidentate manner (N–Hg2+–N), which resulted in a significant color change from light red to violet due to aggregation. Using this PEI-AuNP probe, determination of Hg2+ ion can be achieved by the naked eye and spectrophotometric methods. Pronounced color change of the PEI-AuNPs in the presence of Hg2+ was optimized at pH 7.0, 50°C, and 300 mM·NaCl concentration. The absorption intensity ratio (A700/A514) was correlated with the Hg2+ concentration in the linear range of 0.003–5.0 μM. The limits of detection were measured to be 1.72, 1.80, 2.00, and 1.95 nM for tap water, pond water, tuna fish, and bovine serum, respectively. Owing to its facile and sensitive nature, this assay method for Hg2+ ions can be applied to the analysis of water and biological samples.

A Colorimetric Aptamer Biosensor Based on Gold Nanoparticles for the Ultrasensitive and Specific Detection of Tetracycline in Milk

2013 ◽  
Vol 66 (4) ◽  
pp. 485 ◽  
Author(s):  
Lan He ◽  
Yanfang Luo ◽  
Wenting Zhi ◽  
Yuangen Wu ◽  
Pei Zhou
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Colour Change ◽  
Raw Milk ◽  
Hexadecyltrimethylammonium Bromide ◽  
Specific Detection ◽  
Wide Range

This paper proposes a sensing strategy which employs an aptamer, unmodified gold nanoparticles (AuNP), and hexadecyltrimethylammonium bromide (CTAB) to detect tetracycline (TET) in raw milk. The method is based on the colorimetric assay of aggregating AuNP. In the absence of TET, the CTAB and aptamer form a complex which allows the aggregation of AuNP. In the presence of TET, the TET aptamer is exhausted first due to the formation of aptamer-TET complexes, which prevents assembly of the CTAB–aptamer supramolecule, causing a colour change and no aggregation of AuNP. This mechanism for the detection of TET proved to be sensitive and convenient. The colorimetric assay has a detection limit of 122 nM TET. This sensor has great potential for the sensitive, colorimetric detection of a wide range of molecular analytes.

scholarly journals Robust colorimetric detection based on the anti-aggregation of gold nanoparticles for bromide in rice samples

RSC Advances ◽  
2018 ◽  
Vol 8 (38) ◽  
pp. 21566-21576 ◽  
Author(s):  
Siwat Plaisen ◽  
Wilairat Cheewasedtham ◽  
Thitima Rujiralai
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Detection ◽  
Colorimetric Sensor ◽  
Selective Detection ◽  
Bromide Ions ◽  
Rice Samples

In this work, we developed a AuNP colorimetric sensor for the facile, sensitive and selective detection of bromide ions in rice samples.

Colorimetric Detection of Melamine Based on Poly-Thymine Stabilized Gold Nanoparticles

2013 ◽  
Vol 790 ◽  
pp. 619-622
Author(s):  
Chong Jin ◽  
Hui Min Zhao ◽  
Meng Liu ◽  
Jun Ping Tian ◽  
Xie Quan
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Limit Of Detection ◽  
Pure Water ◽  
Colorimetric Detection ◽  
Colorimetric Method ◽  
Milk Powder ◽  
Aggregation Process ◽  
Naked Eye ◽  
Fresh Milk

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.

scholarly journals Development of label-free gold nanoparticle based rapid colorimetric assay for clinical/point-of-care screening of cervical cancer

2020 ◽  
Vol 2 (12) ◽  
pp. 5737-5745
Author(s):  
Tejaswini Appidi ◽  
Sushma V. Mudigunda ◽  
Suseela Kodandapani ◽  
Aravind Kumar Rengan
Keyword(s):  
Cervical Cancer ◽  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Label Free ◽  
Free Gold ◽  
Clinical Point

“C-ColAur” technique for colorimetric detection of cervical cancer by in situ formation of gold nanoparticles.

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