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Analytical Chemistry
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Gas Chromatography (time of Scan or selected ion flight) Mass Spectrometry, monitoring low resolution GC-TOF Comprehensive Gas Chromatography (time of flight) Mass Spectrometry, low resolution GCXGC-TOF Scan or selected ion monitoring; normal column configuration (nonpolar - polar) or reversed column configuration (polar - nonpolar)
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).
Development of a Mathematical Model for Calculating the Cetane Number of Diesel Fuel Based on Their Hydrocarbon Composition and Intermolecular Interactions of Mixture Components
Published in Combustion Science and Technology, 2021
M.V. Maylin, E.V. Frantsina, A.A. Grinko
GC-MS (Gas Chromatograph with Mass Spectrometric Detector) system from Agilent. A mass spectrometric detector (in addition to the integrated FID) is a time-of-flight tube (QTOF), which allows to record ion masses up to 0.0001 amu, which significantly increases the resolution of the device compared to the standard GC-MS systems, where mass registration takes place generally with an accuracy of 0.1 amu. Moreover, the time-of-flight mass spectrometric detector allows to work in MS-MS mode, because of integrated hexapole collision cell. In MS-MS mode, it is possible to identify the most complex molecular structures. Also, this GC-MSQTOF is equipped with an LTM II module, which allows to work in two-dimensional chromatography mode (GCxGC). The GCxGC mode simplifies the work with complex matrices of organic substances, which are difficult or actually impossible to separate under the conditions of the standard one-dimensional mode (Lorentz et al. 2017, Soares et al. 2013). The full name of the device: Agilent 7890 (GC) – 7200 QTOF (MS) with the LTM-II module for two-dimensional chromatography.
Polycyclic musks in the environment: A review of their concentrations and distribution, ecological effects and behavior, current concerns and future prospects
Published in Critical Reviews in Environmental Science and Technology, 2021
Jianv Liu, Wenying Zhang, Qixing Zhou, Qingqin Zhou, Yu Zhang, Linfang Zhu
Method detection limits (MDLs) below 32 ng/L have been successfully applied to real samples with no significant differences. HHCB and AHTN are chiral substances, and several tertiary production impurities are isomers. If all stereoisomers and enantiomers are considered, tandem mass spectrometry cannot overcome the obstacle of having to separate approximately 30 peaks with similar mass spectra. To solve this problem, comprehensive two-dimensional gas chromatography (GCxGC) was applied. Relić et al. (2017) assessed the state of waters in Belgrade regarding pollution with musk compounds using comprehensive orthogonal two-dimensional gas chromatography with mass spectrometry (GCxGC/TOF-MS) as the final analytical method. GCxGC/TOF-MS was also used to determine a group of high-priority EOCs in wastewater and river water (Gomez, Herrera, Sole, Garcia-Calvo, & Fernandez-Alba, 2011), including six synthetic musk fragrances, and excellent results were obtained for the separation efficiency and musk compound identification. GCxGC has great power in the detection of PCMs and could be further developed and applied widely (Hu et al., 2011).