Ambient characterization of synthetic fibers by laser ablation electrospray ionization mass spectrometry

Direct analysis of synthetic fibers under ambientconditions is highly desired to identify the polymer, the finishesapplied and irregularities that may compromise its performanceand value. In this paper, laser ablation electrospray ionizationion mobility time-of-flight mass spectrometry (LAESI-IMSTOF-MS) was used for the analysis of synthetic polymers andfibers. The key to this analysis was the absorption of laser lightby aliphatic and aromatic nitrogen functionalities in thepolymers. Analysis of polyamide (PA) 6, 46, 66, and 12 pelletsand PA 6, 66, polyaramid and M5 fibers yielded characteristicfragment ions without any sample pretreatment, enabling theirunambiguous identification. Synthetic fibers are, in addition,commonly covered with a surface layer for improved adhesionand processing. The same setup, but operated in a transient infrared matrix-assisted laser desorption electrospray ionization (IRMALDESI)mode, allowed the detailed characterization of the fiber finish layer and the underlying polymer. Differences in finishlayer distribution may cause variations in local properties of synthetic fibers. Here we also show the feasibility of massspectrometry imaging (MSI) of the distribution of a finish layer on the synthetic fiber and the successful detection of local surfacedefects

Laser Ablation Electrospray Ionization Hydrogen/Deuterium Exchange Ambient Mass Spectrometry Imaging

Contains fulltext : 224887.pdf (Publisher’s version ) (Open Access

Mass-Spectrometry-Based Identification of Synthetic Drug Isomers Using Infrared Ion Spectroscopy

Contains fulltext : 219869.pdf (publisher's version ) (Open Access

Isomer-Specific Two-Color Double-Resonance (IRMS3)-M-2 Ion Spectroscopy Using a Single Laser: Application in the Identification of Novel Psychoactive Substances

Contains fulltext : 231408.pdf (Publisher’s version ) (Open Access

Structural Elucidation of Agrochemicals and Related Derivatives Using Infrared Ion Spectroscopy

[Image: see text] Agrochemicals frequently undergo various chemical and metabolic transformation reactions in the environment that often result in a wide range of derivates that must be comprehensively characterized to understand their toxicity profiles and their persistence and outcome in the environment. In the development phase, this typically involves a major effort in qualitatively identifying the correct chemical isomer(s) of these derivatives from the many isomers that could potentially be formed. Liquid chromatography-mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy are often used in attempts to characterize such environment transformation products. However, challenges in confidently correlating chemical structures to detected compounds in mass spectrometry data and sensitivity/selectivity limitations of NMR frequently lead to bottlenecks in identification. In this study, we use an alternative approach, infrared ion spectroscopy, to demonstrate the identification of hydroxylated derivatives of two plant protection compounds (azoxystrobin and benzovindiflupyr) contained at low levels in tomato and spinach matrices. Infrared ion spectroscopy is an orthogonal tandem mass spectrometry technique that combines the sensitivity and selectivity of mass spectrometry with structural information obtained by infrared spectroscopy. Furthermore, IR spectra can be computationally predicted for candidate molecular structures, enabling the tentative identification of agrochemical derivatives and other unknowns in the environment without using physical reference standards

Untargeted metabolomics and infrared ion spectroscopy identify biomarkers for pyridoxine-dependent epilepsy

BackgroundPyridoxine-dependent epilepsy (PDE-ALDH7A1) is an inborn error of lysine catabolism that presents with refractory epilepsy in newborns. Biallelic ALDH7A1 variants lead to deficiency of α-aminoadipic semialdehyde dehydrogenase/antiquitin, resulting in accumulation of piperideine-6-carboxylate (P6C), and secondary deficiency of the important cofactor pyridoxal-5'-phosphate (PLP, active vitamin B6) through its complexation with P6C. Vitamin B6 supplementation resolves epilepsy in patients, but intellectual disability may still develop. Early diagnosis and treatment, preferably based on newborn screening, could optimize long-term clinical outcome. However, no suitable PDE-ALDH7A1 newborn screening biomarkers are currently available.MethodsWe combined the innovative analytical methods untargeted metabolomics and infrared ion spectroscopy to discover and identify biomarkers in plasma that would allow for PDE-ALDH7A1 diagnosis in newborn screening.ResultsWe identified 2S,6S-/2S,6R-oxopropylpiperidine-2-carboxylic acid (2-OPP) as a PDE-ALDH7A1 biomarker, and confirmed 6-oxopiperidine-2-carboxylic acid (6-oxoPIP) as a biomarker. The suitability of 2-OPP as a potential PDE-ALDH7A1 newborn screening biomarker in dried bloodspots was shown. Additionally, we found that 2-OPP accumulates in brain tissue of patients and Aldh7a1-knockout mice, and induced epilepsy-like behavior in a zebrafish model system.ConclusionThis study has opened the way to newborn screening for PDE-ALDH7A1. We speculate that 2-OPP may contribute to ongoing neurotoxicity, also in treated PDE-ALDH7A1 patients. As 2-OPP formation appears to increase upon ketosis, we emphasize the importance of avoiding catabolism in PDE-ALDH7A1 patients.FundingSociety for Inborn Errors of Metabolism for Netherlands and Belgium (ESN), United for Metabolic Diseases (UMD), Stofwisselkracht, Radboud University, Canadian Institutes of Health Research, Dutch Research Council (NWO), and the European Research Council (ERC)