Basics Of Gas Chromatography Mass Spectrometry System
Raquel Cumeras, Xavier Correig in Volatile organic compound analysis in biomedical diagnosis applications, 2018
Mass spectrometry is a destructive method of chemical analysis, which provides detailed chemical and structural information regarding the compounds of interest, based on its mass to charge (m/z) ratio and subsequent mass fragmentation patterns; the MS data can be used for structure elucidation and compound identification. Within MS, there are two forms of mass measurements (Kokkonen, 1999) (1) low resolution or unity mass measurement, and (2) accurate or hi-resolution MS measurements. In unity MS measurements, the m/z measurement is reported in the form of the positive integer only (i.e., 121 m/z), whereas, in hi-resolution MS, the m/z measurement is given as a positive integer to 4–5 decimal places (i.e., 121.0457). This difference is non-trivial and is based on the actual atomic mass of the elements itself. Therefore, the more precise the MS measurement, the more accurate the interpretation/inferences can be made regarding the potential elemental composition. Hi resolution MS measurement enables empirical formula to be calculated with greater confidences. The MS patterns of approximately 250,000–400,000 chemical compounds have been characterized and curated within publically available databases such as Human Metabolome Data Base (Wishart, 2012), METLIN (Smith, 2005), Massbank (Horai, 2010), as well as the National institute of standards and technology (NIST) (Halket, 1999).
Emerging Biomedical Analysis
Lawrence S. Chan, William C. Tang in Engineering-Medicine, 2019
After completing this chapter, the students should: Understand the engineering, physics and chemistry principles of mass spectrometry.Understand the three major steps of mass spectrometry.Understand the potential applications of mass spectrometry in medicine.Understand the application of mass spectrometry in cancer diagnostics. Able to understand the mechanism of intraoperative tumor margin identification by mass spectrometry.Understand the limitations and challenges of popularizing the utilization of mass spectrometry in medicine.Be able to apply mass spectrometry in a real-life medical situation.
Analysis Update—Full Spectrum Cannabis
Betty Wedman-St Louis in Cannabis as Medicine, 2019
GC and HPLC have one thing in common with respect to detection: both instruments can utilize the very powerful mass spectrometer (MS). There are several types of mass spectrometers, but the most common are single quadrupole and triple quadrupole. Examples of single quadrupole mass spectrometers are GCMS and LCMS, while the triple quadrupole mass spectrometers are GC-MS/MS and LC-MS/MS (Figure 21.3). In situations where a single or triple quadrupole mass spectrometer could be used, the acronyms GCMS(/MS) or LCMS(/MS) may be used. A GC-MS/MS could be used in the single quadrupole GCMS mode for the analysis of terpenes. This is important because an analyst using a GC-MS/MS for contaminant testing of pesticides could also operate in the GCMS mode for terpene analysis. An LCMS(/MS) can be used to analyze amino acids and flavonoids. In the LC-MS/MS mode, the same instrument and detector could also measure contaminants like pesticides and mycotoxins/aflatoxins. Generally speaking, an MS(/MS) can replace all other detectors.
Structured sparse support vector machine with ordered features
Published in Journal of Applied Statistics, 2022
Kuangnan Fang, Peng Wang, Xiaochen Zhang, Qingzhao Zhang
In this section, we apply our methods to a dataset of Ovarian Dataset 8-7-02. The dataset is provided by the US Food and Drug Administration (FDA) and the National Cancer Institute (NCI), which can be downloaded and accessed at http://home.ccr.cancer.gov/. The data were collected as serum samples from normal and cancer patients, and the mass spectrometry technique was combined with the WCX2 protein chip and SELDI-TOF. The sample set included 91 controls and 162 ovarian cancers, which were not randomized. Each mass spectrometer sample contains a 15154-dimensional mass-to-charge ratio (m/z) /intensity characteristic. As mentioned in Section 1, the features are ordered in a meaningful way. Following the original researchers, we ignored m/z-sites below 100, where chemical artifacts can occur [16].
Untargeted metabolomics-assisted comparative cytochrome P450-dependent metabolism of fenbendazole in human and dog liver microsomes
Published in Xenobiotica, 2022
Young-Heun Jung, Dong-Cheol Lee, Jong Oh Kim, Ju-Hyun Kim
Advancements in strategies for mass spectrometry-based drug metabolism studies have evolved remarkably in recent decades (Wen and Zhu 2015). Recently, liquid chromatography–mass spectrometry (LC–MS)-based metabolomic techniques have been introduced and actively applied in drug metabolism studies (Chen et al. 2007; Meyer and Maurer 2012). The comparison of global mass spectral data between the control and in vitro or in vivo drug treatment groups enables the effective identification of drug metabolites (Kim et al. 2018a, 2018b). Multivariate analyses, such as principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), are generally conjugated in the untargeted metabolomics approach for distinguishing between groups and for effective examination of the relative quantitative data of drug metabolites (Gromski et al. 2015; Worley and Powers 2013). Metabolomics is an excellent tool for species comparison studies of drug metabolism because of these characteristics (Kim et al. 2017, 2018c). Recently, untargeted metabolomics combined with feature-based molecular networking has become a strategy in drug metabolism studies, and the outcomes have revealed novel discoveries and insights (Le Dare et al. 2020; Quinn et al. 2017; Yu et al. 2022). Overall, the metabolomic approach is an efficient and unbiased tool for identifying drug metabolites and for metabolic comparisons between species.
Fast protein sequencing of monoclonal antibody by real-time digestion on emitter during nanoelectrospray
Published in mAbs, 2019
Yuan Mao, Lichao Zhang, Andrew Kleinberg, Qiangwei Xia, Thomas J. Daly, Ning Li
After protein was denatured, reduced, and desalted (see Materials and Methods), the sample was transferred to a sample plate on the Advion TriVersa NanoMate®, which was mounted on a Thermo Orbitrap mass spectrometer system.23 Protease XIII was then added at the desired enzyme to substrate ratio (w/w). The enzyme and protein were mixed by pipetting up and down. The TriVersa NanoMate® infusion mode was triggered immediately afterward. The infusion mandrel first retrieved an infusion tip, then drew the sample. The infusion tip was then engaged to the electrospray ionization (ESI) chip. Subsequently, nanospray ESI and Orbitrap data acquisition were triggered. Tandem mass spectrometry data was acquired for 30 min. The total time for sample preparation and data acquisition was approximately 1 h.
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