Real divisors and pseudo‐continuous enhancement of resolution for a Kendrick mass defect analysis

Fouquet, Thierry; Nakamura, Sayaka; Sato, Hiroaki; Cody, Robert B.

doi:10.1002/rcm.8500

Cited by 7 publications

(8 citation statements)

References 14 publications

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“…Pyrolysis-GC/MS profiles composed of 3480 scans were exported as netCDF files using the proprietary program msAxel (JEOL, Japan), which was also used for the control of the instrument. The netCDF files were imported to the freeware Kendo (AIST, Japan) written with Visual Studio (Microsoft, USA) for the processing and visualization of mass spectral data. , All the files were first thresholded at 1000 counts (average background signal from the detector before the py-GC/MS analysis) and “CF 2 -filtered” scan-by-scan to extract any peak series spaced by 49.9968 (mass of a CF 2 moiety) ±0.003 Da, which was the tolerance chosen based on the dispersion of m / z values for the peak from hexamethylcyclotrisiloxane at m / z 207.0324 over 10 min of analysis.…”

Section: Experimental Methodsmentioning

confidence: 99%

Disposition of Fluorine on New Firefighter Turnout Gear

Muensterman

Titaley

Peaslee

et al. 2021

Environ. Sci. Technol.

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Firefighter turnout gear is essential for reducing occupational exposure to hazardous chemicals during training and fire events. Per-and polyfluoroalkyl substances (PFASs) are observed in firefighter serum, and possible occupational sources include the air and dust of fires, aqueous film-forming foam, and turnout gear. Limited data exist for nonvolatile and volatile PFASs on firefighter turnout gear and the disposition of fluorine on the individual layers of turnout gear. Further implications for exposure to fluorine on turnout gear are not well understood. Three unused turnout garments purchased in 2019 and one purchased in 2008, were analyzed for 50 nonvolatile and 15 volatile PFASs by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-qTOF-MS) and gas chromatography–mass spectrometry (GC–MS), respectively. Particle-induced gamma ray emission (PIGE), a surface technique, and instrumental neutron activation analysis (INAA), a bulk technique, were used to measure total fluorine. Bulk characterization of the layers by pyrolysis-GC/MS (py-GC/MS) was used to differentiate fluoropolymer (e.g., PTFE) films from textile layers finished with side-chain polymers. The outer layer, moisture barrier, and thermal layers of the turnout gear all yielded measured concentrations of volatile PFASs that exceeded nonvolatile PFAS concentrations, but the summed molar concentrations made up only a small fraction of total fluorine (0.0016–6.7%). Moisture barrier layers comprised a PTFE film, as determined by py-GC–MS, and gave the highest individual nonvolatile (0.159 mg F/kg) and volatile PFAS (20.7 mg F/kg) as well as total fluorine (122,000 mg F/kg) concentrations. Outer and thermal layers comprised aromatic polyamide-based fibers (aramid) treated with side-chain fluoropolymers and had lower levels of individual nonvolatile and volatile PFASs. Equal concentrations of total fluorine by both PIGE and INAA on the outer and thermal layers is consistent with treatment with a side-chain fluoropolymer coating. New turnout gear should be examined as a potential source of firefighter occupational exposure to nonvolatile and volatile PFASs in future assessments.

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Section: Experimental Methodsmentioning

confidence: 99%

Disposition of Fluorine on New Firefighter Turnout Gear

Muensterman

Titaley

Peaslee

et al. 2021

Environ. Sci. Technol.

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“…Kendrick analysis of the MALDI-MS data was performed by importing the raw data retrieved from the FlexAnalysis software into an Excel program developed at AIST (Advanced Industrial Science and Technology, Tsukuba, Japan) . The Kendrick mass (KM) values of the observed ions were calculated according to eq , in which R / x is the fractional base unit ( x ≥ 1) used to create Kendrick plots and m / z the ion’s mass-to-charge ratio. − The corresponding Kendrick mass defects (KMDs) were obtained according to eq , i.e., by subtracting the KM from the nominal mass of the ion (NKM). Kendrick displays were derived by plotting Kendrick mass defect (KMD) vs m / z .…”

Section: Methodsmentioning

confidence: 99%

Elucidation of Low Molecular Weight Polymers in Vehicular Engine Deposits by Multidimensional Mass Spectrometry

Snyder

Wesdemiotis

2020

Energy Fuels

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Engine oil is mainly comprised of base oils and various additives, which are low molecular weight polymers mixed into the oil resulting in a polymer blend. Dispersants and detergents, the two most abundant additives, are intended to keep the engine free of particulate but are not always successful. At high temperatures, species not combusted may undergo oxidation and degradation or create other byproducts, generating particulate deposition. Knowledge of the molecular makeup of these byproducts is essential, as particulate accumulation can cause serious issues to the engine and ultimately to the operator. In this study, unknown deposits from the air-intake valve of a vehicular engine have been analyzed via a palette of mass spectrometry (MS) methods, including matrix-assisted laser desorption/ionization MS with postacquisition data processing, atmospheric solids analysis probe MS, and electrospray ionization MS interfaced with 2D separation via reversed-phase liquid chromatography and ion mobility spectrometry. Low molecular weight, aminated poly(propylene glycol) and polyisobutylene detergents and a poly(methyl methacrylate) viscosity modifier were conclusively identified in the deposit, along with oxidized polyethylene chains leaked into the oil/additives blend from vehicular tubing and tanks. The use of different methods was essential for the confident elucidation of the low molecular weight macromolecules giving rise to the vehicular engine particulates.

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“…The profile spectra exported from msTornado analysis (JEOL) were turned into peak lists using mMass 5.5.0 28 (Gaussiansmoothing; window size: 0.01 m/z; peak-picking F I G U R E 1 DIUTHAME mass spectra of PEG 600 observed using the DIUTHAME chip threshold: 0.5%). The KMD plots were computed and processed from the peak lists using Kendo, 29 an in-house program.…”

Section: Kendrick Mass Defect (Kmd) Analysismentioning

confidence: 99%

Molecular characterization of polyethylene oxide based oligomers by surface‐assisted laser desorption/ionization mass spectrometry using a through‐hole alumina membrane as active substrate

Sato

Nakamura

Fouquet

et al. 2020

Rapid Comm Mass Spectrometry

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Rationale Molecular characterization of industrial oligomeric products is performed using surface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS), termed desorption ionization using a through‐hole alumina membrane (DIUTHAME). This paper describes the unique feature of a DIUTHAME chip applying active SALDI, which generates specific types of fragments of polyglycol samples. Methods Polyethylene oxide (PEO) and PEO‐based materials were subjected to SALDI‐MS. The influence of the presence or absence of a cationization salt on the mass spectrum was investigated. The resulting mass spectra composed of fragment ions were compared with those obtained by collision‐induced dissociation (CID)‐MS/MS. The specific fragment ions generated using the DIUTHAME chip were further subjected to high‐energy CID‐MS/MS. Results The addition of a cationization salt resulted in SALDI mass spectra with fewer fragment peaks. The mass spectra obtained without adding the cationization salt were composed of many more fragment ions caused by in‐source decay. The fragmentation pattern was similar to that seen with low‐energy CID. The resulting fragment ions were formed by selective cleavage at the C‐O bond. High‐energy CID‐MS/MS can be performed for the specific fragment ions generated by in‐source decay fragmentation. Conclusions Molecular characterization of PEO‐based oligomers by SALDI‐MS using the DIUTHAME chip was successfully demonstrated. The selective fragmentation and high‐energy CID‐MS/MS of the in‐source decay fragments made it possible to provide more detailed structural information. This unique feature of DIUTHAME gives it potential for use in new molecular characterization techniques.

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Real divisors and pseudo‐continuous enhancement of resolution for a Kendrick mass defect analysis

Cited by 7 publications

References 14 publications

Disposition of Fluorine on New Firefighter Turnout Gear

Disposition of Fluorine on New Firefighter Turnout Gear

Elucidation of Low Molecular Weight Polymers in Vehicular Engine Deposits by Multidimensional Mass Spectrometry

Molecular characterization of polyethylene oxide based oligomers by surface‐assisted laser desorption/ionization mass spectrometry using a through‐hole alumina membrane as active substrate

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