Here’s our latest summary of news items where volatile organic compounds (VOCs) have been the focus of attention.
Malaria makes mouse odour more appealing to mosquitoes
Researchers from Swiss Federal Institute of Technology in Zurich, Switzerland, have shown that the volatile blends released from malaria-infected mice make them more attractive to mosquitoes. Mark Mescher and colleagues found that the attractiveness increased significantly after acute symptoms had subsided but while the mice remained highly infectious. This supports the hypothesis that the malarial parasite is manipulating the mouse’s odour for its own benefit – in this case, by maximising the probability of the mouse being bitten by more mosquitoes, and so spreading the parasite.
In a separate experiment, VOC profiles from healthy and malaria-infected mice were investigated using a chamber to sample volatiles from the live mice onto an absorbent, followed by analysis using GC–MS and GC–FID. The researchers found that overall volatile emissions fell during the early, acute stage of infection, but then periodically increased during the later stages. They found 11 compounds to be important predictors of infection status during the chronic phase of the disease, while only one compound – 2-hexanone – was an important predictor of infection status during both the chronic and postchronic phases.
These findings could lay the foundation of a method to disrupt signalling from infected animals to mosquitoes, as well as indicating diagnostic biomarkers. The authors describe their work as “an important proof of concept regarding the identification of volatile biomarkers of malaria infection”.
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World Health Organisation calls for indoor e-cigarette ban
E-Cigarettes remain in the media spotlight, with a report from the WHO calling for their use indoors to be prohibited, and for e-cigarette advertising to be restricted. The report found insufficient evidence to support a conclusion that e-cigarettes help users quit smoking, points out that e-cigarette aerosol is not merely “water vapour” as is often claimed, and says that although the devices are less toxic than conventional cigarettes, they may pose threats to susceptible groups.
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The smell of money
A Californian firm, KWJ Engineering, has identified the chemical fingerprint of banknotes. One hundred $1 bills in various states (from fresh to used) were incubated at 23°C and 40°C, and the volatiles collected onto an SPME fibre, with analysis by TD–GC–MS. The profiles were found to vary considerably from note to note, but a common ‘signature’ was eventually found, which included aldehydes, furans and organic acids at “a small fraction of a ppm”. The next challenge, they say, will be to implement this technology in a backpack device that can be used by border guards to detect smuggling.
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Food analysts look to advanced GC techniques for chemical fingerprinting
An article in Laboratory Talk, including interviews with industry analysts, highlights how chemical fingerprinting using GC×GC–TOF MS could play its part in tackling the issues highlighted by the recent Elliot Review into the integrity and assurance of food supply networks.
In the article, Julian South from food testing firm Campden BRI says “There is a lot of talk that chemical fingerprinting is going to become a routine form of analysis for contract labs in the near future”. This comment is mirrored by Dionisis Theodosis from analytical laboratory Exova, who says “I am quite optimistic about chemical fingerprinting”. However, both scientists caution that the whole concept of chemical fingerprinting is some way from being a routine tool in the hands of food chemists.
VOCs from petroleum industry can cause ozone pollution in winter as well as summer
Low-level ozone normally occurs where high levels of VOCs are exposed to strong summer sunlight, but this isn’t always the case – and now research led by Steven Brown at NOAA Earth System Research Laboratory, Boulder, USA, has shown how this happens.
In a paper published in the journal Nature, they use computer simulations to model observations made in a remote Utah oilfield over a sequence of three winters. They found that rapid ozone production in winter could result from a combination of high VOC emissions into a shallow, stable boundary layer, and increased photolysis due to reflected light from snow-cover.
The authors say that winter production of ozone could have “as yet unrecognised consequences”, especially in regions that experience stable winter weather, and that their study will help to better define this emerging air quality issue.
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