However, reliable measurement methods that enable large numbers of samples to be analysed quickly and economically would need to be in place in order to make comprehensive monitoring a reality. In the latest issue of the scientific journal Angewandte Chemie, the group led by Renato Zenobi, Professor of Analytical Chemistry at the Organic Chemistry Laboratory of ETH Zurich, has presented a method that successfully meets these requirements.
Based on a standard instrument
The new procedure of analysis represents a further development of the method recently published by the group in which the researchers successfully detected various substances in the breath in a simple manner. Using their enhanced method, they can now also very precisely track down substances on surfaces of any kind. Both methods are based on what is called a ‘quadrupole time-of-flight mass spectrometer’ (QTOF mass spectrometer). Zenobi explains that “such measuring instruments are routinely used in many areas nowadays.” Samples for QTOF mass spectrometry are normally presented in solution. The solution is electrosprayed, with the additional aid of a desolvation gas. The tiny droplets give rise to ions that are characteristic of the substance to be analysed and which the QTOF instrument measures.
The ETH Zurich researchers have now almost turned the principle on its head: instead of studying the substances in the solution, they now examine the substances present in the desolvation gas assisting the spray. With the newly-developed method nitrogen is blown from a small nozzle onto a sample surface. As the gas strikes the surface it desorbs semi-volatile substances. The “en-riched” gas stream is then fed into the mass spectrometer where the absorbed substances can be precisely analysed.
Equipment modification in less than an hour
Professor Zenobi says «There is nothing special about the new method from a technical viewpoint.» Huanwen Chen, who has developed the method during his post-doctoral studies in Zenobi’s group, impressively demonstrated this when together with his supervisor he presented the new method to a company. Within one hour Chen had modified their mass spectrometer so that it could be used to analyse the surface of any kind of object.
However, the remarkable aspect of the new method is the wide variety of possibilities it opens up. «One particular strength of our approach is that even the surfaces of living organisms can be examined. It only takes a few seconds to measure a single sample; so large numbers of random samples can be routinely analysed», Zenobi says. For meat samples the scientists were also able to show that the sample material does not even need to be thawed.
Numerous possible applications
The studies carried out by the researchers on the skin of various test persons lead in quite a different direction. Traces of nicotine, coffee and explosives could all be detected on the skin. According to Zenobi «The method’s strength is that it is fast and non-invasive, and needs no special sample preparation.» In view of the numerous possible applications, it is not surprising that the new method is of interest not only to foodstuffs technologists and safety experts but also to medical professionals and drugs investigators in sport.
Roman Klingler | alfa
Research offers clues for improved influenza vaccine design
09.04.2018 | NIH/National Institute of Allergy and Infectious Diseases
Injecting gene cocktail into mouse pancreas leads to humanlike tumors
06.04.2018 | University of Texas Health Science Center at San Antonio
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy