Online Supercritical Fluid Chromatography Hyphenated to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Quadrupole Detection for Microalgae Bio-Oil Characterization.

Microalgae are an attractive feedstock for biofuel production thanks to their renewable nature, high growth rate, and ability to use anthropogenic CO2. The conversion of microalgae by hydrothermal liquefaction (HTL) leads to a solid residue, a gaseous phase, and a biocrude. However, the bio-oil is rich in heteroatoms and requires upgrading processes to be used as biofuels. For these treatments to be effective, detailed knowledge of the sample is crucial. The bio-oil was characterized by direct introduction into a Fourier transform ion cyclotron resonance mass spectrometer (DI-FTICR MS) with an electrospray ionization source (ESI). Thousands of molecular formulas were assigned with a high level of confidence, mainly compounds with nitrogen and oxygen atoms. Additionally, the bio-oil was analyzed by coupling supercritical fluid chromatography (SFC) and FTICR to combine the separation power of SFC to the high performances of a 12 T FTICR. Quadrupole detection (2ω) was used in FTICR to have a high resolving power with a lower transient time. The coupling allowed the separation of many isomers along the chromatogram, showing the isomeric complexity of microalgae bio-oils. Moreover, classes of compounds were separated according to their heteroatom class thanks to the SFC separation. In this work, the advantages of DI-FTICR MS and SFC-FTICR MS proved complementary, and DI was useful to study the bio-oil at the molecular scale thanks to the high performances, while SFC proved useful for the characterization at the isomeric scale. This demonstrated the significant potential of this new online hyphenated technique for the characterization of complex matrices.

Quantifying Phospholipids in Organic Samples Using a Hydrophilic Interaction Liquid Chromatography-Inductively Coupled Plasma High-Resolution Mass Spectrometry (HILIC-ICP-HRMS) Method.

In this study, a novel method using hydrophilic interaction liquid chromatography (HILIC) coupled with inductively coupled plasma high-resolution mass spectrometry (ICP-HRMS) was introduced for the quantification of phospholipids in oil samples. The method employed a bridged ethyl hybrid (BEH) stationary phase HILIC column with a tetrahydrofuran (THF)/water mobile phase, enhancing the solubility and detection of phospholipids. During the study, a gradient/matrix effect on ICP-HRMS sensitivity was observed and successfully compensated for experimentally, ensuring reliable quantification results. This approach has proven effective for a wide range of different oil samples including vegetable oils, animal fats, and phospholipid supplements. Notably, this method allowed the direct quantification of phospholipids in oil samples, bypassing the need for prior sample preparation methods, such as solid phase extraction (SPE), thereby streamlining the analytical process. The precision, accuracy, and reduced need for extensive sample preparation offered by this method mark a significant advancement in lipids analysis. Its robustness and broad applicability have substantial implications for industries such as food and renewable energy production, where both efficient and accurate lipid identification and quantification are crucial.

Analysis of Thermoplastic Copolymers by Mild Thermal Degradation Coupled to Ion Mobility Mass Spectrometry.

Thermal desorption/degradation with an atmospheric solids analysis probe (ASAP) and ion mobility (IM) separation are coupled with mass spectrometry (MS) analysis and tandem mass spectrometry (MS/MS) fragmentation to characterize thermoplastic elastomers. The compounds investigated, which are used in the manufacture of a wide variety of packaging materials, are mainly composed of thermoplastic copolymers, but also contain additional chemicals ("additives"), like antioxidants and UV stabilizers, for enhancement of their properties or protection from degradation. The traditional method for analyzing such complex mixtures is vacuum pyrolysis followed by electron or chemical ionization mass spectrometry, often after gas chromatography separation. Here, an alternative, faster approach, involving mild degradation at atmospheric pressure (ASAP) and subsequent characterization of the desorbates and pyrolyzates by IM-MS, and if needed, MS/MS is presented. Such multidimensional dispersion considerably simplifies the resulting spectra, permitting the conclusive separation, characterization, and classification of the multicomponent materials examined.

Characterization of Polyolefin Pyrolysis Species Produced Under Ambient Conditions by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Ion Mobility-Mass Spectrometry.

Polyolefins such as polyethylene (PE) and polypropylene (PP) are often characterized from their pyrolysis products by Py-MS. Nowadays the development of plasma-based direct probe atmospheric pressure sources allow the direct analysis of these polymers. These sources operate at atmospheric pressure, which implies a limited control of the ionization conditions. It was shown that side reactions could occur with species present in air, such as O2, which may lead to the formation of oxidized compounds. In this work, ion mobility-mass spectrometry (IM-MS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR) were used for the exhaustive characterization of the PP and PE pyrolysis ions produced using plasma-based atmospheric pressure ion sources. Both PP and PE yielded distributions of pyrolysis products presenting different amounts of unsaturation but also different numbers of oxygen atoms. In addition, the ions produced from PP presented a lower collision cross-section (CCS) than those produced from PE. In the same way, both PP and PE present repeated patterns separated by 14 m/z in the bidimensional drift time versus m/z plots. Within these plots, several trend lines can be evidenced, which are specific of each polymer investigated. Differences were observed between isotactic and atactic samples concerning the pyrolysis profile relative abundance and collision cross-section. Graphical Abstract ᅟ.