Many materials and products we use on a daily basis have a characteristic odor. If this odor is unpleasant or arises suddenly, the identification of all odorous substances in the relevant product can have important implications. In order to identify the causes, possible negative physiological effects, and opportunities for odor optimization, we carry out qualitative and quantitative sensory analytics. We identify possible reaction pathways and precursor substances that contribute to odor formation. Our detailed knowledge of material properties is also utilized to develop strategies to avoid or minimize odor formation in a wide range of products and materials.
The characterization of odorants is performed using gas chromatography-olfactometry (GC-O) coupled with mass spectrometry (MS). The use of GC-O enables clear distinction between odorous substances, including off-odors, and non-odorous substances. The analysis also enables direct comparison of different samples and identification of undesired components.
The identification of odorous trace components is performed using high performance two-dimensional GC-O/MS. Here the odorous substances are separated on two coupled GC columns and then analyzed by a mass spectrometer. The odor quality is also evaluated at an odor detection port by highly trained sensory specialists.
The resulting instrumental-chemical information is then compared with the human-sensory evaluations to ensure that all off-odors are identified.
The technique of proton-transfer-reaction mass spectrometry (PTR-MS) - often coupled with time-of-flight mass spectrometry (PTR-TOF-MS) - is regularly employed for the real-time analysis and quantitation of VOCs. The PTR-MS method allows small changes in the concentration of VOCs to be monitored down to ultra-trace levels. Real-time analysis is vital because important emissions processes are often transient, for example, mechanical or enzymatic processes associated with mastication. We use PTR-MS for both in vivo analyses (e.g. nosespace analysis) and in vitro analyses (e.g. headspace analysis).
In addition to PTR-MS, ion mobility spectrometry (IMS) and other advanced two-dimensional thermal desorption (TD)GCxGC-MS systems are used for analyzing VOCs. This enables the characterization of VOCs with a high resolution. Gas samples can be collected on sorbent tubes (e.g. Tenax) using a micro-chamber/thermal extractor, with subsequent analysis by GC-MS following thermal desorption.
Many plastics and recyclates have unpleasant odors. In particular, plastics produced from recycled post-consumer waste often do not meet the quality requirements of the packaging industry. We characterize odorous contaminants and develop customized solutions for odor optimization or minimization.
Toys and other children's products often have a distinct odor. We identify these volatile components, possible reaction pathways, and their effect on the human body. We have already found that many substances lead to off-odors and irritation.
The characteristic odor of wood has been little researched to date. We evaluate odorous substances in wood using advanced analytical methods used in food aroma research. We determine what odorous substances in wood transfer to downstream products such as paper and cardboard and determine any changes during the manufacturing process.
We can quantify volatile compounds in many other non-food products and materials, for example: