Aromatic gases are widely present in food, pharmaceuticals, cosmetics, and various daily chemical products, such as snacks, liquors, spices, traditional Chinese medicine, plasters, perfumes, soaps, and shampoos. Unlike inorganic gases and water vapor, most aromatic gases are emitted by the products themselves and are an important quality and primary function (and sometimes the only function) of these products. The presence of aromatic gases plays a crucial role in these products; their loss or increase directly affects product quality and sales. Therefore, maintaining the types and concentrations of aromatic gases is a key indicator of product quality. However, achieving the detection of aromatic gas permeability has always been a global challenge. Currently, Labthink Gas Permeation Laboratory is dedicated to developing and implementing this test. 1. The Necessity of Aromatic Gas Permeability Testing The odors and aromatic gases we refer to here are various organic gases, not just aromatic compounds in the traditional sense. They are intricately linked to product quality. Sometimes these are the actual "products," such as perfumes and air fresheners. If the aromatic gases dissipate, the "product" for sale disappears. The same applies to some medicines; for example, the loss of the scent of a plaster is equivalent to the loss of its efficacy. Sometimes they are key to sales, such as "flavored" foods, specialty products, or high-end tobacco and alcohol. Sometimes they can influence sales. For example, for most cosmetics, different scents affect sales; if the fragrance dissipates, even if the product's function remains intact, it may not be able to sell. Furthermore, all these products share a common enemy: "odors" from outside the packaging. Even a slight infiltration of an odor can directly affect the scent inside the packaging, rendering the product unsellable and unusable. Therefore, when packaging these products with special scents, materials with excellent aromatic gas barrier properties must be selected to prevent the escape of aromatic gases and the infiltration of odors. 2. Current Status of Aromatic Gas Permeability Testing During the permeation of aromatic gases into packaging materials, the diffusion coefficient D and solubility coefficient S are affected by the permeate in the polymer, belonging to non-Fick type permeation. The most prominent manifestation is that the material will experience internal swelling and other changes in the polymer structure due to the internal reaction between the permeate and the polymer. This manifests as a significant deviation between the actual measured permeation volume and the predicted FICK curve as the permeation time increases (while the measured gas permeation data for FICK-type permeation will coincide well with the predicted FICK curve), as shown in Figure 1. The aromatic gas permeability test method is suitable for determining the aromatic gas permeability of materials such as plastic films and sheets. The test principle involves placing the sample in a permeation chamber at a certain temperature, dividing the chamber into two parts: one side is a high-concentration aromatic gas side, maintaining a specific aromatic gas concentration; the other side is a low-concentration aromatic gas side, continuously purged with a carrier gas flow to maintain a certain aromatic gas concentration difference between the two sides of the sample. The aromatic gas permeating through the sample enters the low-concentration side and is carried out of the permeation chamber by the carrier gas flow. The detection system determines the aromatic gas content in the carrier gas and calculates the aromatic gas permeation volume of the sample. However, many problems arise in actual aromatic gas detection, such as the possibility of aromatic gases reacting with flexible packaging materials during permeation, making the detection more complex. Moreover, compared to air permeability and moisture permeability testing, aromatic gas permeability testing involves a wider range of fields, including not only barrier properties testing and polymer materials, but also material analysis. Therefore, both the establishment of experimental methods and the development of testing equipment make aromatic gas permeability testing far more challenging than current conventional barrier property testing. Furthermore, researching the aromatic gas permeability of materials and conducting aromatic gas permeability testing requires a strong theoretical foundation in permeation research and extensive experience in barrier property testing. 3. Odor Permeation Laboratory Today, with the widespread adoption of barrier property testing and the increasing attention paid to product quality by consumers and manufacturers, many new testing needs are emerging. For industries such as food, pharmaceuticals, cosmetics, and daily chemicals, although the permeation of aromatic gases may not necessarily cause product deterioration or affect hygiene indicators, it can be a key factor influencing product sales. Therefore, the demand for aromatic gas permeability testing is very broad. Labthink is one of the world's earliest manufacturers of packaging material testing equipment to enter the field of barrier property testing. It has extensive experience in testing and researching conventional gas and water vapor permeation and is also one of the earliest professional companies internationally to attempt aromatic gas permeability testing. Labthink has always prioritized meeting customer needs and continuously enriching its cutting-edge testing technologies. Therefore, over the past decade, Labthink has invested significant resources in barrier property theory research and equipment development, resulting in a series of barrier property testing devices and several valuable research achievements. To meet the growing demand for aromatic gas permeability testing, Labthink developed the OPT-01 Organic Gas Permeation Analyzer in 2007. This instrument can quantitatively detect the permeation of various organic gases, such as benzenes, esters, alcohols, aldehydes, and ketones, through films. A dedicated odor permeation laboratory has also been established to conduct research, testing, and services related to aromatic gas permeability. The aim is to improve the packaging effectiveness of products with specific odor requirements and control packaging costs by testing the barrier properties of packaging materials against aromatic gases. The odor permeation laboratory is currently conducting a quantitative organic gas permeation testing project using an instrumental method developed independently by Labthink, while also researching and testing the permeation mechanism of organic gases through polymers. This project aims to provide effective detection and control solutions, offering quality control methods for odor-preserving packaging in the food and cosmetic industries. 4. Conclusion The permeation process of aromatic gases into packaging materials differs from that of conventional gases and water vapor. However, the amount of aromatic gases permeating through packaging materials can be a key factor influencing product sales. Therefore, the market demand for aromatic gas permeability testing is growing rapidly. Since its inception, Labthink Odor Permeability Laboratory has been dedicated to the research and testing of aromatic gas permeability, while also providing testing services to clients, offering more support in material selection and structural design for packaging with fragrance preservation requirements. Editor: He Shiping