SPECIALTY OLFACTOMETRY

Chapter I - Definitions of Different Dimensions and Tools

While olfactometry, the science of odors, is commonly known for its environmental application, specialized olfactometry, on the other hand, focuses primarily on products and materials. One stems from the other, or rather, from the remarkable technical and scientific advancements of the other.

The distinctiveness of this science arises from its ability to draw conclusions from genuine investigations, both chemical and olfactory, at thresholds far lower than those encountered in environmental sources.

At the core of this analytical science lie the four usual dimensions of odor analysis

• Odor intensity, on a scale of 0 to 10;
• Hedonic tone determination, ranging from (-5) to (+5);
• Odor quality, through recognition or comparison;
• And finally, odor concentration, expressed in odor units per cubic meter, forming the basis of modern olfactory engineering.

A fifth, considerably more complex dimension, is also employed to further investigations into the identification of the chemical traces composing the odor. This involves gas chromatography coupled with mass spectrometry. Numerous complementary techniques are also utilized to add modules for specific objectives:

• Solid-phase microextraction;
• Chemo-detection for quantifying sulfur compounds;
• Inter-phase sorption extraction;
• Analysis of chemical compounds isolated by dedicated olfactory ports.

The combined and timely use of these different dimensions resolves many cases of olfactory deviations. However, this expertise stems from years of experience and the development of numerous protocols:

• The use of entirely neutral materials, often even medical or surgical grade, such as SS16 stainless steel, treated glass, and numerous odorless products by Dupont?;
• The use of static flow chambers and others in dynamic mode, often specifically dimensioned to determine emission flux per unit area and time for the implicated odoriferous materials;
• Specifically dimensioned sampling boxes for in vivo and in vitro sampling according to the desired analytical conditions;
• Stringent parameters on ultra-pure gases used, as well as preparation conditions not only in the laboratory but also for chemists: no deodorant, no perfume, no gel, no food or drink... the slightest chemical trace carried by personnel or visitors can contaminate an experimental plan or equipment for weeks!

This notion is often misunderstood by those who have never practiced it: just like bloodhounds, our objectives consist of searching for minute traces. A visitor wearing a slightly too strong and persistent perfume can represent thousands of dollars in decontamination costs, systematic dismantling of equipment, etc. It is increasingly common, during our requests for the preparation of certain samples, for us to predict not only whether it is a man or a woman who prepared the samples on the client site, but also which exact perfume that same person was wearing during the sample handling day. This is one of the reasons why the general public is never invited into our clean rooms. Recently, a perfectly well-packaged paper sample was found to be heavily contaminated by cigarette smoke from a delivery driver who was supposed to bring us the package. If the contamination remains fine at the level of parts per billion, we can still potentially carry out our work, but if the contamination reaches the level of parts per million, we will always prefer to request a new sample preparation to avoid significant unnecessary analytical costs. We may often be perceived as finicky chemists, but the fine craftsmanship required by specialized olfactometry demands it, and the general public often struggles to comprehend the world of molecular traces in which we operate.

Chapter II - Unforeseen Realms of Activity

It might come as quite a surprise to the general public, but specialty olfactometry encompasses an immense array of products and materials across various sectors:

• In the automotive sector, particularly within the vehicle interior, the demand for specialty olfactometry is abundant. The multitude of composite materials, plastics, fibers, flame retardants, and acoustic insulation results in what is commonly known as the "new car smell." Regardless of the brand, the resulting odor mix can sometimes pose toxicological risks, including respiratory tract irritation, headaches, and eye irritation. However, these toxicological effects fall outside the purview of specialty olfactometry, which focuses solely on odors and their various dimensions.
• In the pulp and paper industry, also known as specialty paper production, olfactory deviations are extremely common, especially with the increasing use of recycled materials in raw material preparations. Recycled paper bales traverse the globe before processing, exposed to humid docks, sea winds, and torrential rains. The occurrences of raw material contamination are endless and can yield significant surprises in the finished products:

1. Paper tissues with nauseating scents
2. Absorbent papers with bacterial odors of mold
3. Agro-food packaging with fishy odors
4. Toilet paper prompting customer complaints upon each opening
5. Table napkins with car grease odors
6. Luxury cosmetic packaging with alcohol scents

• For the specific domain of personal products, which encompasses a wide range of items designed to meet individual consumer needs such as cosmetics, skincare and haircare products, perfumes, deodorants, and more, specialty olfactometry approaches become much more specific. Occasionally but relatively frequently, an anti-aging cream or any product may develop an olfactory drift requiring a true molecular investigation akin to Sherlock Holmes, employing multiple olfactory dimensions to identify the responsible molecules. However, the needs for such personal products are much broader:

1. Multi-dimensional odor analyses
2. Preparation of quality drift diagrams and definition of acceptable olfactory targets
3. Analyses of olfactory complaints and comparison between compliant and non-compliant products
4. Molecular investigation at extremely low thresholds requiring sample preparations of several dozen hours of contact
5. Determination of olfactory persistence for certain shower gel or shampoo fragrances
6. Certification of odor reduction levels for deodorants and duration without the appearance of unpleasant odors
7. Specific protocols for in-vivo or in-vitro testing
8. Analysis of hedonic tone variation for new fragrance ranges such as hemp-derived products
9. Certification and classification of individual olfactory capabilities of personnel required to judge the olfactory quality of certain productions
10. Market segmentation analysis to assess the success of specific olfactory formulations based on demographic groups corresponding to particular sexual, ethnic, and cultural identities.

One can easily understand, upon realizing such research factor requirements, that a laboratory specialized in agricultural, industrial, or environmental analyses lacks the capacity for such scientific undertakings. This is precisely why, over time, we have established and dedicated an entirely separate division to analyze these highly specific demands and ensure their results. There are more than forty specific domains where the utility of specialty olfactometry makes perfect sense and allows for conclusive ultra-specific analytical needs.

Chapter III - Parameters Defining a Specialty Olfactometry Laboratory

As mentioned earlier, the first element that defines a specialty olfactometry laboratory is its specificity: such a laboratory cannot conduct analyses of pig excrement on Monday and attempt to realistically analyze the latest trend for a developing fragrance or the longevity of a deodorant the next day.

Furthermore, sanitary rules are also paramount. Strangely enough, it is not only in sanitation aspects that such a laboratory can be defined. Much earlier, in the upstream phase, during the design of the equipment to be used, one must already reason as an engineer would for a nuclear-type experiment: the choice of materials and surface types is crucial. Favoring constituent elements that are of medical or even surgical grade is a must: Grade SS16 treated steel, no crevice allowing the accumulation of pollutants or contaminants, etc.

The experience of the personnel and engineers developing the analytical tools is also a predominant element: A laboratory that can tell you that an odor is unpleasant and mention the corresponding odor quality on the odor wheel is very good, but in my humble opinion, it is not enough. A laboratory that can do this but lacks the analytical capacity to quantify the associated odor concentration because its detection scale is too low will be unable to seriously assist in a specialty problem.

To use a medical metaphor, I would say it's a bit like if a blood analysis and serology laboratory told you that you had diabetes but was unable to measure your blood sugar level... You would have to wait until you died of diabetes before such a laboratory could quantify your blood sugar level!

This is often the sad reality that we encounter when reviewing unresolved cases. Chemists have perfectly followed their operational protocols, have quantified the 300 or 400 chemical compounds present but are unable to identify THE molecule responsible for an olfactory non-conformity. CEN, COFRAC, or even SGS and ISO certifications are in no way a guarantee of know-how, quite the contrary. In the case of odor concentration analyses, it is the passion, tenacity, and engineering of the designers that will allow quantifying odors from their first threshold levels of perception, which are the only guarantees of success for this type of Sherlock Holmes-like investigation: any laboratory that confirms that it smells bad but is unable to quantify the associated odor concentration should be immediately downgraded. Offering a specialty olfactometry service means preparing to provide much more than the requirements of market standards, which are all clearly insufficient for this in the current state of affairs.

In essence, the seven main parameters defining a specialty olfactometry laboratory reflect a commitment to excellence, precision, and innovation in the field of olfactory analysis. These facilities play a pivotal role in addressing odor-related challenges across various industries, driving advancements in olfactory science and technology :

• Expertise and Specialization: Unlike conventional laboratories, specialty olfactometry labs possess a high level of expertise in olfactory science. They specialize in the detection, analysis, and interpretation of complex odor profiles across diverse materials and products.
• State-of-the-Art Equipment: Specialized equipment tailored for olfactory analysis is a hallmark of these laboratories. From sensitive odor detection instruments to advanced chromatography-mass spectrometry setups, these facilities are equipped with cutting-edge technology for comprehensive odor assessment.
• Stringent Quality Control: Maintaining rigorous quality control measures is imperative in specialty olfactometry labs. Every step of the analytical process, from sample preparation to data interpretation, adheres to strict quality standards to ensure accurate and reliable results.
• Customized Methodologies: Given the diverse nature of odor-related challenges, these labs develop customized methodologies to address specific analytical needs. Whether it's characterizing fragrance formulations or assessing odor emissions from industrial processes, tailored approaches are designed to meet client requirements effectively.
• Confidentiality and Compliance: Confidentiality is paramount in specialty olfactometry, especially when dealing with proprietary formulations or sensitive client data. These labs prioritize confidentiality agreements and compliance with regulatory guidelines to uphold client trust and confidentiality.
• Interdisciplinary Collaboration: Olfactory analysis often requires interdisciplinary collaboration, involving chemists, sensory scientists, and environmental experts. Specialty olfactometry labs foster collaboration between diverse professionals to tackle complex odor-related issues comprehensively.
• Continuous Innovation: To stay at the forefront of olfactory science, these labs embrace a culture of continuous innovation. They invest in research and development initiatives to explore new methodologies, technologies, and analytical approaches for enhanced odor assessment capabilities.

Chapter IV - Olfactory Epistemology and Personal Journey

Specialty olfactometry had its early beginnings in the 15th century when its primary focus was on quantifying the perception threshold of newly identified chemical molecules. A few milligrams of the sought-after substance were gradually dispersed in a vast room of known dimensions to determine the increasing thresholds of perception and, sometimes, the associated toxicological thresholds.

Over the ensuing centuries, on both sides of the Atlantic, olfactometry, or the science of odor measurement, continued to evolve, often in contrast to chemical identification analyses. From the 1940s to the 1980s, numerous American organizations tirelessly advanced methods and standards associated with odor metrology, notably introducing the concept of D/T, or "Dilution for Threshold." In Europe, particularly in France, the Atomic Energy Commission (CEA) played a pivotal role in advancing both the precision and the widespread use of these standards, especially initially for environmental applications.

These French considerations birthed the concept of odor concentration, frequently expressed in odor units per cubic meter (ou/m3), and the introduction of the CEN13725 standard in 2003 truly facilitated the widespread adoption of this new engineering dimension—odor concentration—across the globe.

On the opposing side, among scent designers and olfaction enthusiasts, specialty olfactometry emerges primarily from the tireless dedication of a select few individuals deeply passionate about odor measurement. On a profoundly personal note, it was a vision over two decades ago to expand our expertise beyond the environmental sector. Together with a small circle of colleagues, we engineered our inaugural dynamic olfactometer, a design from the Odotech company, which we installed in Grasse, on Rue des Palmiers, in 2006. There, we conducted pioneering trials in perfumery and materials. Then, in 2014, we embarked on ventures in cosmetics in New York, fortified by olfactometers from the Canadian company Scentroid. Over recent years, we've hosted all major global brands, engaging in extensive work within increasingly clandestine, confidential, yet refined, delicate, precise, and profoundly impactful spheres.

For me, the odyssey of specialty olfactometry commenced in 1993 within a diminutive consultancy named ETNA, and I take pride in dedicating the past 31 years of my life with fervent passion to this domain—so enigmatic, so clandestine, yet so deeply fulfilling in my daily role as an odor connoisseur.

See you soon for more secrets from the wonderful WORLD of ODORS!

Yann H. Contratto - Senior Odor Expert since 1993

Scientific, technical, and legal olfactory expertise - Author and speaker

?Olf-Actions International 2024 / Yann H. Contratto

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