Researchers from the Faculties of Chemistry and of Materials Science of Lomonosov Moscow State University have developed a new way of increasing the sensitivity of detecting volatile compounds, especially chlorine, using metallic nanoparticles. The work has been published in the Talanta journal.
Metallic nanoparticles, in particular the nanoparticles of gold and silver, are widely used in analytical chemistry. Amongst their uses is creating optical sensors based on the surface plasmonic resonance (the phenomenon of surface plasmon excitation by light) in colloidal solutions and on solid supports.
Modern optical sensors have considerable advantages like high sensitivity, ease of detecting an analytic signal and adjustability of the optical and laboratory analysis parameters. Nevertheless, these devices have certain limitations when it comes to selectivity.
It happens because of aggregative instability of nanoparticles (the particles stick together when collide) which starts to happen during high ionic strength (high intensity of the electric field created by ions). The ion layer formed on the surface of particles is called the double electric layer and is characterized by an electrokinetic potential, also known as the zeta potential. With a decrease in the zeta potential, the electrostatic stabilization of nanoparticles does not happen.
The problem can be solved if the nanoparticles are attached to solid supports; scientists then acquire micro- or nanosensors based on solid particles. There are not many matrix materials for these sensors, and the process of attaching the nanoparticles to supports is not a simple one, so the researchers started working on a problem of modifying the surface of sensor matrices. For that goal they proposed separating the nanoparticles from ions and chemical compounds while retaining their sensitivity.
The Russian chemists invented a technique that combines optical detection using paper test strips with triangular silver nanoparticles spread over them, and dynamic gas extraction (the extraction of a compound from a solution or a dry mixture by means of liquefied gases). Perspectives of this technique were shown by detecting chlorine. Chlorine is often used to purify water, since it destroys the outer shell of bacteria and viruses. Nevertheless, the problem of determining the chlorine concentration in water remains relevant, since the existing techniques are not sensitive enough.
Aleksei Furletov, student of the Department of Analytic Chemistry, Faculty of Chemistry, Lomonosov Moscow State University, one of the paper's authors, says: "The technique developed allows to determine small amounts of gaseous chlorine in the presence of large concentrations of foreign compounds without any sample preparation. This approach can be applied to other analytical systems based on metal nanoparticles, which opens up broad opportunities for the further development of this area of chemical analysis. "
The research was made in collaboration with scientists from Southern Federal University, Rostov State Medical University, and Scientific-Research Institute of Chemical Reagents and Special Purity Chemicals.
Yana Khlyustova | EurekAlert!
Printing complex cellulose-based objects
27.03.2020 | ETH Zurich
A key development in the drive for energy-efficient electronics
24.03.2020 | University of Leeds
Together with their colleagues from the University of Würzburg, physicists from the group of Professor Alexander Szameit at the University of Rostock have devised a “funnel” for photons. Their discovery was recently published in the renowned journal Science and holds great promise for novel ultra-sensitive detectors as well as innovative applications in telecommunications and information processing.
The quantum-optical properties of light and its interaction with matter has fascinated the Rostock professor Alexander Szameit since College.
Researchers at the University of Zurich show that different stem cell populations are innervated in distinct ways. Innervation may therefore be crucial for proper tissue regeneration. They also demonstrate that cancer stem cells likewise establish contacts with nerves. Targeting tumour innervation could thus lead to new cancer therapies.
Stem cells can generate a variety of specific tissues and are increasingly used for clinical applications such as the replacement of bone or cartilage....
An international research team led by Kiel University develops an extremely porous material made of "white graphene" for new laser light applications
With a porosity of 99.99 %, it consists practically only of air, making it one of the lightest materials in the world: Aerobornitride is the name of the...
Researchers at Graz University of Technology have developed a framework by which wireless devices with different radio technologies will be able to communicate directly with each other.
Whether networked vehicles that warn of traffic jams in real time, household appliances that can be operated remotely, "wearables" that monitor physical...
Terahertz waves are becoming ever more important in science and technology. They enable us to unravel the properties of future materials, test the quality of...
26.03.2020 | Event News
23.03.2020 | Event News
03.03.2020 | Event News
27.03.2020 | Power and Electrical Engineering
27.03.2020 | Life Sciences
27.03.2020 | Life Sciences