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Per- and Polyfluoroalkyl Substance Analysis to Support Site Characterization, Exposure, and Risk Management
Published in David M. Kempisty, Yun Xing, LeeAnn Racz, Perfluoroalkyl Substances in the Environment, 2018
Kavitha Dasu, David M. Kempisty, Marc A. Mills
Methods may use single-quadrupole mass spectrometry (MS) or triple-quadrupole tandem mass spectrometry (MS/MS) technique. However, due to the poor selectivity in complex matrices, moderate sensitivity, and matrix interferences, single-quadrupole MS is rarely used for PFAS analysis. Triple-quadrupole MS/MS consists of two quadrupole (Q1 and Q3) mass analyzers in series. When both Q1 and Q3 are set at a specific mass, allowing only a specific fragment ion from a certain parent molecular ion to be detected, it is called selected reaction monitoring (SRM), and if Q1 and Q3 are set to more than a single mass, it is called multiple reaction monitoring (MRM) mode. With the significant increase in selectivity and sensitivity, MS/MS techniques are preferred for PFAS analysis in complex environmental matrices.
Emerging Biomedical Analysis
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
Tandem mass spectrometry (MS/MS or MS2) refers to the combination of two or more mass analyzers in a single mass spectrometer. In a tandem mass spectrometer, ions in a wide mass range are first measured in the first stage of mass spectrometry (MS1); based on the MS1 data, ions within a narrow mass range (precursor ions) are isolated and dissociated; the fragment or product ions are then identified in the second stage of mass spectrometry (MS2). This concept can be extended to multi-stage mass spectrometry (MSn) if the product ions are further isolated, fragmented and measured in the nth stage of mass spectrometry (MSn).
Mass Spectrometry Instrumentation
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Yuan Su, Li-Rong Yu, Thomas P. Conrads, Timothy D. Veenstra
In the 1970s, Cooks et al. proposed the concept of tandem mass spectrometry and established the early generation of instrumentation for analysis of complex mixture by in-vacuum gas collisions (Beynon et al., 1973; Kondrat and Cooks, 1978). Tandem mass spectrometry is a method involving multiple stages of ion selections and fragmentations or chemical reactions occurring between stages (McLafferty, 1981). Typically, direct measurement of the m/z values of ions produced from the ion source is called a full scan (MS1). Unlike the full scan, tandem mass spectrometry involves the selection and isolation of ions in a mass analyzer as the first MS analysis stage, the fragmentation or gas reaction between the two MS analysis stages, and the generation of MS2 spectra of product ions in the second MS analysis stage. This process can be achieved either by using successive mass analyzers spatially or by conducting the steps of MS/MS at separate times. Each precursor ion can produce a unique pattern of product ions with good consistency and better sensitivity than the full scan, so that these diagnostic ions can be used as unambiguous evidence for structural elucidation or confirmation. The most well-known tandem mass spectrometry technique is collision-induced dissociation (CID), which breaks precursor ions by an energy-transfer ion/molecule reaction when the kinetic energy of both precursor ions and inert buffer gas molecules, accelerated by the electric/magnetic field, is converted into internal energy and finally cleaves the weakest bonds of the precursor ions, producing fragments (Wells and McLuckey, 2005). Besides MS/MS, more structural information can be obtained by the fragmentation of product ions or fragmentation in multiple stages, which is called multiple-stage tandem mass spectrometry (MSn). Table 14.1 gives a summary of the typical dissociation methods and the corresponding gas reactions of tandem mass spectrometry for proteomic analysis.
Determination of antibiotic impurities in good manufacturing practices-grade cell therapy medicinal products
Published in Preparative Biochemistry & Biotechnology, 2020
Olga Nehir Oztel, Seval Korkmaz, Erdal Karaoz
Residual tests for the detection of small amount of compound need highly selective and sensitive methods. For that reason, the LC_MS/MS method was selectied for the detection of residual antibiotic in final cell product. High resolution chromatographic separation techniques coupled to accurate tandem mass spectrometry (Liquid Chromatography Tandem-Mass Spectrometry (LC-MS/MS)) can be used for accurate quantitative profiling of proteins and metabolites in complex biological samples.[20–23] The LC-MS/MS method have also been used for determination of antibiotics residues in several manufactured products for humans as well as animals. Despite studies on food and water products,[10,16,24–31] there are no validation studies on using LC-MS/MS for detection of antibiotic residues in ATMPs. In this study, we aimed to determine the presence of penicillin G and streptomycin residues using LC-MS/MS and proposed a novel methodology that can be applied to multiple production steps of cell-based medicinal products and during the preparation of the cells for cultivation in the culture medium in Current Good Manufacturing Practice (cGMP) conditions.
Online measurement of phthalate–particulate matter interactions by membrane introduction mass spectrometry (MIMS)
Published in Journal of Environmental Science and Health, Part A, 2018
Martin A. Angelstad, Erik T. Krogh, George R. Agnes, Chris G. Gill
Comparing of the total ion current signal (Fig. 5A) versus the extracted ion signals at m/z 149 and 163 (Fig. 5B) suggests that a significant fraction of the desorbed compounds are not phthalates. The full scan mass spectra (not shown) are dominated by fragment ions differing by m/z 14, suggesting molecules with aliphatic hydrocarbon structures. No further attempts were made in this study to identify these desorbed compounds. Although beyond the scope of the present work, the future use of alternative ionization sources, tandem mass spectrometry, and/or high resolution mass analyzers will enable improved confidence in making measurements for different classes of analytes, as well as identification of unknown compounds.