Project description:<p>The development of improved spectrometers and supporting computational tools is expected to eventually enable the rapid annotation of whole metabolomes. However, rarely are novel mass spectrometers directly compared to the previously used ones in the field of metabolomics, thus preventing researchers from gauging the benefits of the investment. LC Orbitrap technology is now widely in use while GC-Orbitrap introduced in 2015 has remained fairly unexplored in its potential for metabolomics research. This study aims to evaluate the additional knowledge gained in a metabolomics experiment when using the GC-Orbitrap in comparison to a unit mass singlequad GC-MS. Samples from an osmotic stress treatment versus a control of the microalga Skeletonema costatum were investigated using comparative metabolomics. Samples from this treatment of a non-model organism were split and measured on both platforms with nearly identical chromatography. Resulting datasets were compared both on a statistical level and on the level of individual compound annotation. Both mass spectrometers successfully classified stressed vs non-stressed microalgae, but the GC-Orbitrap detected more than triple the number of compounds compared to the singlequad mass analyzer, resulting in more readily interpretable annotations. Additionally, one unknown was correctly annotated exploiting high resolution capabilities unavailable to the singlequad mass analyzer. While computational support that specifically utilizes high resolution GC-MS data is still underdeveloped, clear benefits of the GC-Orbitrap technology for metabolomics studies are shown here.</p>
Project description:This is the GC Orbitrap data accompanying the FluoroMatch GC Library manuscript.
References and software are available here:
https://innovativeomics.com/software/fluoromatch-gc-modular-pfas-annotation/
Despite thousands of documented PFAS, approaches to characterize volatile and semi-volatile PFAS are limited. To address this gap, we developed a non-targeted gas chromatography high-resolution mass spectrometry (GC-HRMS) workflow to extend coverage of volatile and semi-volatile PFAS. This workflow includes new FlouroMatch GC mass spectral libraries (>1900 EI and PCI predicted and experimental spectra) and characterization of thousands of PFAS specific EI fragments for fragment screening. Liquid chromatography (LC) and GC-HRMS approaches were highly complementary, with GC-HRMS revealing diverse PFAS profiles in 8 different environmental and biological matrices distinct from PFAS detected in LC approaches. For example, we detected a previously unreported PFAS, 2-(perfluorohexyl)ethanethiol in multiple firefighting foam (AFFF) formulations and a novel feature tentatively annotated as N-methyl-N-(2-hydroxyethyl) perfluorooctanesulfonamide (MeFOSE alcohol) that was consistently detected in various matrices related to point and non-point PFAS exposures including dried blood spots, leachate, industrial effluent, and settled dust collected from homes, which were not detected in corresponding LC approaches. Personal exposure to volatile and semi-volatile PFAS was found to vary significantly across individuals. In a cohort of 48 children in Connecticut wearing wristband passive samplers, GC-HRMS fragment screening revealed that 46% of 40 unique airborne PFAS detected only occurred in a single child, and 58% of 47 unique PFAS detected in settled dust collected from 11 households were only detected in a single home. Findings highlight the importance of personal monitoring using a combination of non-targeted GC and LC-HRMS approaches to comprehensively characterize PFAS exposures. The novel methods that we have established will allow the health burden PFAS to be rigorously evaluated, ultimately informing regulatory policies and public health interventions.
Project description:The overall aroma is an important factor of the sensory quality of fruit wines, which attributed to hundreds of volatile compounds. However, the qualitative determination of trace volatile compounds is considered to be very challenging work. GC-Orbitrap-MS with high resolution and high sensitivity provided more possibilities for the determination of volatile compounds, but without the high-resolution mass spectral library. For accuracy of qualitative determination in fruit wines by GC-Orbitrap-MS, a high-resolution mass spectral library, including 22 esters, 11 carbonyl compounds, 10 high alcohols, 7 lactones, 6 acids, 6 furans, 5 pyrazines, 5 terpenes, 4 benzenes, 4 volatile phenols and 1 sulfide, was developed in this study. Not only the HRMS spectrum but also the exact ion fragment, relative abundance, retention indices (RI), CAS number, chemical structure diagram, aroma description and aroma threshold were provided and were shown in a database website (Food Flavor Laboratory, http://foodflavorlab.cn/). HRMS library was used to successfully identify the volatile compounds mentioned above in 16 fruit wines (5 blueberry wines, 6 goji berry wines and 5 hawthorn wines). The library was developed as an important basis for further understanding of trace volatile compounds in fruit wines.
Project description:Normalized relative abundance measurement of amines in B. fragilis P207 (NCBI accession NZ_CP114371) culture using GC-EI-MS with methoxyamine and TMS derivatization.
Project description:Axon regeneration in the central nervous system (CNS) requires reactivating injured neurons’ intrinsic growth state and enabling growth in an inhibitory environment. Using an inbred mouse neuronal phenotypic screen, we find that CAST/Ei mouse adult dorsal root ganglion neurons extend axons more on CNS myelin than the other eight strains tested, especially when pre-injured. Injury-primed CAST/Ei neurons also regenerate markedly in the spinal cord and optic nerve more than those from C57BL/6 mice and show greater spouting following ischemic stroke. Heritability estimates indicate that extended growth in CAST/Ei neurons on myelin is genetically determined, and two whole-genome expression screens yield the Activin transcript Inhba as most correlated with this ability. These screens are presented here.