TECHNOLOGY | ODOUR AND EMISSIONS
detect odours in many industries, particularly food and beverage, and can also be used to detect impurities in polymers. French company Alpha MOS has been refining its signature Heracles Neo E-nose since launch in 2018, with the recent focus on saving time while increasing analysis capabili- ties. The company says the aim is to streamline the technology while accuracy and viability of the collected data is being improved through the use of artificial intelligence (AI) and statistical analysis tools in tandem with its large proprietary database of molecules and sensory attributes.
Testing services UK-based Olfasense (formerly Odournet UK) offers a range of sensory and molecular testing and analysis services to identify, measure, and forecast environmental odours, assess odour impact, and evaluate emissions. “There are different ways of processing and
evaluating material samples, so the first thing we’ll do is help you choose the right method, based on your industry and the plastic’s intended use,” according to a company spokesperson. “Our techniques embrace both reference sensory testing methods (for example, ISO 16000- 28, VDA 270, VDI 3882, EN 13725, discrimination testing, descriptive analysis, etc), as well as chemi- cal-sensory analysis (GC-MS, GC-Sniffing-MS, GC-IMS). This provides a complete overview of the plastic’s odour perception from the consumers’ perspective and/or from the objective assessment of a trained panel, as well as the understanding of the chemical compounds that are responsible for the odour itself,” the company says. Another company offering lab instruments for detection and identification of odours in polymers is SepSolve Analytical, which has facilities in Europe and North America. “Unfortunately, existing methods to monitor emissions from PCR plastics all suffer from limitations,” says Product Marketing Manager Dr Laura McGregor. “Human sensory panels are a sensitive approach to detecting odours, but they are also subjective, time-consuming and require skilled individuals. They only provide sensory information and not chemical identification, so cannot indicate the possible source or clean-up processes required. Alternatively, handheld E-nose devices use simple sensor technology to evaluate emissions but they are not specific, meaning that samples that fail quality control testing must undergo further investigation to ascertain their source,” she says. “Laboratory-based techniques, such as gas chromatography coupled with mass spectrometry
42 COMPOUNDING WORLD | July 2023
(GC–MS), can separate and identify the individual chemicals emitted from plastics, but may struggle to detect all the compounds present. The emission profiles are often dominated by compounds from the polymer itself, which mask odorants present in low levels. Additionally, common ways of introduc- ing the samples to the laboratory instruments may lack the necessary sensitivity to detect trace-level odorants in the first place,” she says. “With such approaches, it is often not possible to identify the precise compounds responsible for malodours, meaning that the recycling process cannot be improved. Failures further down the production chain are costly, with losses accumu- lated through returned products or compensation claims,” according to McGregor.
Concentrating samples SepSolve Analytical claims to have developed an end-to-end workflow incorporating advanced analytical instrumentation to overcome these challenges, she says. Thermal desorption (TD) is used to extract and pre-concentrate emissions from the plastic prior to analysis. Improved separation is then achieved using two-dimensional gas chroma- tography (GC×GC), which separates based on two different chemical properties rather than one. This pulls the odorous compound away from the poly- mer. Then, by combining GC×GC with a time-of- flight mass spectrometry (TOF MS) detector, a characteristic signature is recorded for each individu- al compound, allowing it to be confidently identified. “This detailed level of information is essential for
the recycling processes so methods and records can be updated,” McGregor says. “This approach is more complex than [using] a handheld e-nose device, but the system can be simplified for use in high-throughput, quality control laboratories. Additionally, prediction models can be incorpo- rated to instantly classify future samples as either a pass or fail.”
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.luxus.co.uk �
www.ampacet.com �
www.milliken.com �
www.byk.com �
www.lbf.fraunhofer.de �
www.aimplas.net �
https://ecosorbindustrial.com �
www.fraunhofer.de �
https://www.ivv.fraunhofer.de/en.html �
www.alpha-mos.com �
www.olfasense.com �
www.sepsolve.com
www.compoundingworld.com
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