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Insight into Knapsack Metabolite Ecology Database: A Comprehensive Source of Species: Voc-Biological Activity Relationships
Published in Raquel Cumeras, Xavier Correig, Volatile organic compound analysis in biomedical diagnosis applications, 2018
Azian Azamimi Abdullah, M.D. Altaf-Ul-Amin, Shigehiko Kanaya
Advancement in analytical methods such as gas chromatography-mass spectrometry (GC-MS), proton transfer reaction mass spectrometry (PTR-MS) and selected ion flow tube mass spectrometry (SIFT-MS) have provided an opportunity to identify the volatile metabolites of living organisms in research laboratories. These analytical approaches generate a large amount of data and require specialized mathematical, statistical and bioinformatics tools to analyze such data. Despite the advances in sampling and detection by these analytical methods, only a few databases have been developed to handle these large and complex datasets. There are some VOC databases, which can be accessed freely. However, their applicability is often limited by several elements. Most of these databases only focus on volatiles, which are emitted by certain living organisms and have limited applications. None of these databases provide information on biological activities of VOCs and species-species interaction based on volatiles. To meet this purpose, we have developed a VOC database of microorganisms, fungi, and plants as well as human being, which comprises the relation between emitting species, volatiles and their biological activities (Abdullah et al., 2015). We have deposited the VOC data into KNApSAcK Metabolite Ecology Database, and this database is currently available at http://kanaya.naist.jp/MetaboliteEcology/top.jsp. Also, the database can be accessed online by clicking the corresponding button in the main window (Figure 9.1). Apart from the database development, we also analyzed the VOC data using hierarchical clustering and network clustering based on DPClus algorithm. In addition, we also performed the heatmap clustering based on Tanimoto coefficient as the similarity index between chemical structures to cluster all VOCs emitted by various biological species to understand the relationships between chemical structures of VOCs and their biological activities.
Human Odor: An Overview of Current Knowledge and Experimental Designs
Published in G. Thilagavathi, R. Rathinamoorthy, Odour in Textiles, 2022
Analytical techniques for the characterization of human body VOCs have been reviewed in the literature (Duffy and Morrin 2019; Kataoka et al. 2013). Instrumentation for their analysis is commonly conducted with gas chromatography coupled with mass spectrometry (GC-MS), the gold standard detection system for VOC odor profile analysis due to its capacity for simultaneous analysis of a large number of compounds, coupled with built-in identification mechanisms, as seen with mass spectral libraries. GC is also advantageous as the odor components released from the human body are mostly VOCs, which have a high vapor pressure and thus are ideal for GC separation. A new analytical trend has been observed with the introduction of multidimensional chromatographic systems. Studies have begun implementing comprehensive two-dimensional gas chromatographic time-of-flight mass spectrometry (GCxGC-TOFMS) for the analysis of emissions from ankles, wrists, and hands (Cuzuel et al. 2018; Dolezal et al. 2017; Roodt et al. 2018). Direct MS methods, such as selected ion flow tube mass spectrometry (SIFT-MS), proton transfer reaction mass spectrometry (PTR-MS), membrane inlet mass spectrometry (MIMS), and secondary electrospray ionization mass spectrometry (SESI-MS), have also been used. GC has also been coupled with ion mobility spectrometry (IMS), as well as the use of electronic noses (e-nose), for skin VOC detection (see reviews, Pandey and Kim 2011; Duffy and Morrin 2019). In terms of biological detection, canines have been a standard for detection of humans in a range of law enforcement and forensic applications (Agapiou et al. 2015; Prada, Curran, and Furton 2015). Due to the volatility of these personal odor signatures, canines represent a dynamic detection system, with low threshold characteristics, amenity to work in high contamination, and ease of being deployable to operational settings. Although it is still unknown which volatile odor markers are specific for canine use in human odor detection, it has been established that there is enough variation within an individual's odor profile for canines to not only detect human odor but also to perform discrimination on odor samples (Prada, Curran, and Furton 2015).
V-shaped ion funnel proton transfer reaction mass spectrometry
Published in Instrumentation Science & Technology, 2019
Yujie Wang, Kexiu Dong, Yannan Chu
Proton transfer reaction mass spectrometry (PTR-MS) is a well-developed and commercially available technique for monitoring trace volatile organic compounds (VOCs). With the advantages of rapid response, high sensitivity, and soft ionization, PTR-MS is becoming an important tool applied in the environmental field, food control, medical applications, water detection, and security.[1–5] To improve the identification of VOCs, several approaches have been experimentally attempted since its inception including changes in the reduced-field E/N[1] where E is the electric field and N is the buffer gas number density, new reagent ions,[6] other mass analyzers,[7–9] and novel sampling methods.[3,10,11]