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
Biofilm discovery suggests new way to prevent dangerous infections
23.05.2017 | University of Texas at Austin
Another reason to exercise: Burning bone fat -- a key to better bone health
19.05.2017 | University of North Carolina Health Care
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy