Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Arsenic and Gold Clusters

25.11.2009
Fast, easy, and highly sensitive arsenic detection with gold nanoparticles

Mention of arsenic poisoning usually brings to mind underhanded murder. However, the danger of arsenic poisoning from contaminated drinking water is far greater. Low concentrations of arsenic are found in nearly all soils and thus also in ground water.

About 140 million people worldwide possibly drink water that contains arsenic concentrations above the WHO-recommended limit of 10 ppb (parts per billion). Researchers at Jackson State University (MS, USA) have now developed a new approach for a rapid, easy, and highly sensitive arsenic test.

As Paresh Chandra Ray’s team reports in the journal Angewandte Chemie, their method is based on the aggregation of gold nanoparticles, and it selectively detects arsenic in drinking water down to concentrations of 3 ppt (parts per trillion).

Countries like India, Bangladesh, and Thailand are primarily affected by ground water with high arsenic concentrations. However, high concentrations of arsenic have also been found in some areas of North and South America. Once detected, the problem can fairly easily be addressed. Current analytical techniques are time-consuming and require a series of enrichment steps.

The new process could now speed up and simplify arsenic analysis. The scientists working with Ray have attached special organic molecules to the surfaces of gold nanoparticles. These molecules act as “ligands” for arsenic, meaning that they form a complex with it. Each arsenic ion can bind to three ligands, which allows it to link together up to three gold particles. The higher the arsenic concentration in the sample, the more strongly the gold particles clump together and the number of bigger aggregates increases. The color of gold nanoparticles in a liquid depends on their size. Whereas the arsenic-free gold nanoparticles appear red, arsenic-induced aggregation causes the color to change to blue. Concentrations down to 1 ppb can be detected with the naked eye by means of the color change. Arsenic binds to the ligands much more strongly than other metals; the researchers were able to increase this selectivity by attaching three different ligands to the gold.

One very precise method for detecting minimal changes in particle size is dynamic light scattering (DLS), in which laser light scattered by the particles is analyzed. By using DLS, Ray and his co-workers were able to detect and quantify arsenic concentrations as low as 3 ppt. In samples of well water from Bangladesh, the team found 28 ppb arsenic; in water from taps in Jackson (Mississippi, USA) they found 380 ppt.

Author: Paresh Chandra Ray, Jackson State University (USA), http://chem.jsums.edu/ray/

Title: Use of Gold Nanoparticles in a Simple Colorimetric and Ultrasensitive Dynamic Light Scattering Assay: Selective Detection of Arsenic in Groundwater

Angewandte Chemie International Edition 2009, 48, No. 51, 9668–9671, doi: 10.1002/anie.200903958

Paresh Chandra Ray | Angewandte Chemie
Further information:
http://pressroom.angewandte.org
http://chem.jsums.edu/ray/

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

Topologische Quantenchemie

21.07.2017 | Life Sciences

Pulses of electrons manipulate nanomagnets and store information

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>