The latest thinking in odour and emissions from plastics – News from Kassel 2019
Tuesday, 16 April 2019 at 1:23:PM
What’s new in the VOC analysis of plastics?
For 20 years the conference ‘Odour and Emissions of Plastic Materials’ – often known simply as ‘Kassel’ after the German city where it’s always held – has been the place where analysts from Europe and beyond go to find out the
answer to this question.
As the Material Emissions Specialist at Markes, it was a
exciting for me to attend Kassel this year for the first time, and discover the
latest research trends in investigating VOC emissions from polymers and related
materials. Here are a few highlights.
The keynote lecture at Kassel 2019 was on microplastics – a
highly topical area, given the global attention currently focused on the issue
of plastic pollution. Dr Ulrike Braun from the Bundesanstalt für
Materialforschung und -prüfung (BAM), Berlin, explained how his team have been
developing a method to identify microplastic polymers in air and water, which
has previously been challenged by time-consuming sample preparation, as well as
issues of reproducibility caused by limitations in sample size.
Dr Braun’s method involves the complete thermal
decomposition of relatively large plastic samples, and extraction of the
resulting products onto a sorptive phase, followed by TD–GC–MS. We were shown
how this was being applied to identification of waterborne plastics, and it was
especially interesting to see the results of preliminary work on the tiny
fragments of plastic in air and dust.
Can you predict odorous
emissions from plastics?
Several presentations at 'Odour and Emissions of Plastic
Materials’ were focused on the topic of odour profiling of plastics and
correlation to sensory data, and in keeping with our own experience over many
years, researchers been finding that off-odours are usually caused by trace-level
The upshot of this is that the overall odours of polymers
can be very difficult to predict – an effect exacerbated by the difficulty in
understanding how the human nose responds to individual molecular structures.
Christoph Wiedmer from the Fraunhofer Institute for Process
Engineering and Packaging IVV, Freising, provided conclusive evidence of this
in his presentation (see examples from his slides opposite), with his comment “there is no way
of predicting the odour qualities of unknown substances based on their
Odour compounds in
leather – What’s the best sampling method?
Did you know that leather must undergo 47
manufacturing procedures before it’s ready for consumer use? I certainly didn’t
until I heard this remarkable statistic in the talk by Thomas Simat of
Technische Universität Dresden.
Apart from being introduced to the curious terminology used
in this field – including bating, frizing, sammying, fication and
curtain-coating – attendees at Kassel learnt about how Dr Simat and colleagues
have been comparing the differences in VOC emissions from leather at the
various stages of production.
A key aspect of Dr Simat’s talk was a comparison of methods
used to isolate the odour-active substances from the leather matrix.
Solvent-assisted flavour extraction (SAFE) has a reputation as being laborious and
strongly dependent on the solvent extraction step, while simultaneous
distillation extraction (SDE) has a tendency to show temperature-related artefacts.
In contrast, concentrating the analyte on a bed of sorbent –
we’ve used in our own work (direct desorption of VOCs and SVOCs from leather furnishings)
– was found to closely mirror the conditions experienced by the consumer, and
was the only method that enabled the effect of humidity to be investigated. Dr
Simat described how they were consequently able to identify over 50 compounds,
and so develop ‘odour sticks’ for key odorants, to be used as reference
The challenge of
identifying sulfur odorants in vehicle interior air
For the first time ever, there was representation at Kassel
from the China Automotive Technology & Research Centre. CATARC are a
long-standing customer of Markes, and Dr Yanmeng Wang from the organisation’s
Tianjin facility gave a thought-provoking presentation on the latest in testing
of vehicle interior air quality (VIAQ).
Vehicle odour is of course a crucial issue for Chinese
consumers, and CATARC are at the forefront of developing a GB/GBT standard to
perform VIAQ testing. Dr Wang explained that the current focus of the group is
the semi-quantitation of sulfur compounds, which pose the triple challenge of
being present in small quantities, being odour-active at low levels, and requiring
highly inert analytical systems. He also presented a comparison of sample
collection and analysis methods, and the potential of e-nose systems to speed
up odour detection.
As highlighted in this presentation, the decision on the
best technique to use is clearly not always an easy one, especially when
challenging analytes are involved, and we’ve been working with CATARC to help
them get the best out of their TD system for this application.
Equipment for investigating VOC emissions from polymers
As well as being successful for the organisers, ‘Odour and
Emissions of Plastic Materials’ at Kassel was also a great event from our point
of view, with plenty of contacts made with new and existing customers at our
booth, and interest in our poster on VOC emissions from medical devices
Download poster – Monitoring VOC emissions from respiratory medical devices in accordance with the new ISO 18562 method
In particular, a lot of existing users of our Micro-Chamber/Thermal
Extractor wanted to know more about our new accessories for preparing spray
polyurethane foam samples
If you’d learn about how these could help you improve the way you sample VOC emissions
from materials, just drop me a line at
Kassel is always an interesting conference, and
I’m already looking forward to seeing how much this rapidly-changing area will
have evolved by this time next year!
Nikhil Sahotra is the Material Emissions Specialist at Markes International. His role focuses on the sampling and analysis of volatile organic compounds in air, as well as those emitted by products and materials. Prior to joining Markes, Nikhil received a Master’s degree in medicinal chemistry from Newcastle University, and subsequently was awarded a Ph.D. in organic electro/photoluminescent materials from the University of Birmingham.