Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Colorful Warning

Selective, sensitive CO detection with a rhodium complex

Carbon monoxide is an insidious poison: it is colorless, odorless, and toxic at low concentrations. It is usually produced by combustion engines or incomplete combustion in gas furnaces or wood-burning fireplaces.

Spanish researchers working with Ramón Martínez-Máñez have now developed a sensitive and selective detector that reliably detects CO in air. As the scientists from the IDM Research Institute at the Polytechnic University of Valencia report in the journal Angewandte Chemie, their system involves a special rhodium complex that distinctly changes color in the presence of CO.

In the USA alone, there are 15,000 accidents with CO reported annually; 500 of these are fatal. The implementation of reliable warning devices in dangerous locations is thus correspondingly important. Most modern CO sensors are electronic; as an alternative, researchers are looking for detectors that indicate the presence of CO by a color change. However, such colorimetric detection methods remain rare, don’t function in air, or are not sensitive enough.

Based on a special complex of rhodium, the Spanish researchers have now developed a CO detector that not only reliably detects CO in solution, but also in air. The detection limit is low enough that it responds before toxic levels are reached.

At the core of the complex are two rhodium atoms connected to each other by acetate groups and two special phosphorus-containing ligands (cyclometallated phosphines). The metals are also bound axially by two acetic acid ligands. The complex molecule is deposited onto silica gel, where it is adsorbed; this forms a gray-violet solid. If the complex comes into contact with air containing CO, one or two molecules of CO bind to the rhodium by forcing the acetic acid molecules out of their axial binding sites on the two rhodium atoms. Within a few minutes, this causes a distinct color change in the solid, which becomes orange-yellow. Treatment with a stream of clean air completely regenerates the detector.

The detection system is highly selective for CO. It does not respond to CO2, volatile organic compounds, or SO2. It only reacts to NO2 when it is present in extremely high concentrations. The researchers hope that this system will form the basis for efficient, low-maintenance chemosensors for the easy and inexpensive detection of CO. “For instance colorimetric detection systems of CO can be implemented in clothes, paintings etc.,” says Martínez-Máñez, “and the presence of CO will then simply be detected via a color change visible to the naked eye”. In contrast, electronic equipment needs a source of electricity and is difficult to incorporate into the fabric of clothes.

Author: Ramón Martínez-Máñez, Universidad de Valencia (Spain),

Title: Sensitive and Selective Chromogenic Sensing of Carbon Monoxide using Binuclear Rhodium Complexes

Angewandte Chemie International Edition 2010, 49, No. 29, 4934–4937, Permalink to the article:

Ramón Martínez-Máñez | Angewandte Chemie
Further information:

More articles from Life Sciences:

nachricht First-time reconstruction of infectious bat influenza viruses
25.10.2016 | Universitätsklinikum Freiburg

nachricht The nanostructured cloak of invisibility
25.10.2016 | Max-Planck-Institut für Intelligente Systeme

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

The nanostructured cloak of invisibility

25.10.2016 | Life Sciences

Oasis of life in the ice-covered central Arctic

24.10.2016 | Earth Sciences

‘Farming’ bacteria to boost growth in the oceans

24.10.2016 | Life Sciences

More VideoLinks >>>