Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Fixing by Filtration

Abstract:
New testing strips for detecting heavy metals

Fixing by Filtration

Posted on January 03, 2006

Many heavy meals are toxic to the environment or to humans. Legal limits for these pollutants in drinking water and run-off are thus correspondingly low. Rapid on-the-spot analysis and routine water quality tests demand a rapid, cost-effective method that doesn’t require complex instruments. Test strips that indicate the presence and concentration of a heavy metal when simply dipped into the water are ideal. Commercially available strips are currently not sufficiently reliable or sensitive. Japanese researchers have now developed a new generation of test strips that meet these high demands. Their secret is pigment nanocrystals that are fixed to a membrane filter by means of simple filtration.

One of the main problems of current testing strips for heavy metals is that the reagents can be washed out, which significantly reduces their effectiveness. A truly satisfactory process for the fixation of pigments was previously unknown. A research team headed by Toshishige M. Suzuki has now discovered a very simple method for fixing the heavy-metal-specific color reagents to the test strips so that they can neither be washed away by the test solution nor rubbed off. They were thus able to produce testing strips that react specifically to divalent zinc, mercury, and iron.

The color reagent must first be formed into nanoscopic particles. The pigment is thus dissolved in an organic solvent and then sprayed into vigorously stirred water. Because the pigment is not water-soluble, it crystallizes out, and under these conditions it crystallizes in the form of nanocrystals that are finely dispersed in the solution. When filtered through a cellulose membrane, 99.5 % of the nanoparticles stick to the membrane surface in a fine, dense, even layer. This precise control of the amount of pigment applied is an important requirement for testing strips that give reproducible results. The continuous layer of the color reagent makes the strips highly sensitive, allowing the detection of zinc ions at concentrations as low as 65 ppb (parts per billion). Lower detection limits can be achieved by the filtration of larger amounts of the test solution through the reagent-coated membrane.

This new method for the production of testing strips can be used for many water-insoluble color reagents, allowing for the development of a large family of metal-specific testing strips.

####


Author: Toshishige M. Suzuki, AIST Tohoku (Japan), unit.aist.go.jp/lmc/english/staff/staff_01.htm

Title: Test Strips for Heavy-Metal Ions Fabricated from Nanosized Dye Compounds

Angewandte Chemie International Edition, doi: 10.1002/anie.200503015

Contact:
Editorial office:
angewandte@wiley-vch.de

or David Greenberg (US)
dgreenbe@wiley.com

or Julia Lampam (UK)
jlampam@wiley.co.uk

Copyright © Angewandte Chemie

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Materials/Metamaterials

EmTech Asia breaks new barriers with potential applications of space exploration with NASA and MIT February 22nd, 2017

Molecular phenomenon discovered by advanced NMR facility: Cutting edge technology has shown a molecule self-assembling into different forms when passing between solution state to solid state, and back again - a curious phenomenon in science - says research by the University of Wa February 22nd, 2017

Tiny nanoclusters could solve big problems for lithium-ion batteries February 21st, 2017

Oxford Instruments announces Dr Brad Ramshaw of Cornell University, as winner of the 2017 Lee Osheroff Richardson Science Prize February 20th, 2017

Announcements

Atomic force imaging used to study nematodes: KFU bionanotechnology lab (head - Dr. Rawil Fakhrullin) has obtained 3-D images of nematodes' cuticles February 23rd, 2017

Particle Works creates range of high performance quantum dots February 23rd, 2017

GLOBALFOUNDRIES Announces Availability of 45nm RF SOI to Advance 5G Mobile Communications: Optimized RF features deliver high-performance solutions for mmWave beam forming applications in 5G smartphones and base stations February 22nd, 2017

EmTech Asia breaks new barriers with potential applications of space exploration with NASA and MIT February 22nd, 2017

Water

Nano-level lubricant tuning improves material for electronic devices and surface coatings February 11th, 2017

Tough aqua material for water purification: Decontamination of water with a robust and sustainable membrane assembled from 2 synergistically working components January 24th, 2017

Scientists have discovered a new state of matter for water January 2nd, 2017

PCATDES Starts Field Testing of Photocatalytic Reactors in South East Asia December 28th, 2016

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project