Interfacial electromigration for accelerated reactions.

Background: Microdroplets have emerged as effective confined-volume reactors due to their remarkable ability to accelerate chemical reactions compared to bulk systems. Recent research highlights the crucial role of air-liquid interfaces in this acceleration. A microdroplet can be viewed as having two kinetically distinct regions: the interface and the interior.

Interfacing High-Throughput Electrosynthesis and Mass Spectrometric Analysis of Azines.

Combinatorial electrochemistry has great promise for accelerated reaction screening, organic synthesis, and catalysis. Recently, we described a new high-throughput electrochemistry platform, colloquially named "Legion". Legion fits the footprint of a 96-well microtiter plate with simultaneous individual control over all 96 electrochemical cells.

Interfacial Electromigration for Analysis of Biofluid Lipids in Small Volumes.

Lipids are important biomarkers within the field of disease diagnostics and can serve as indicators of disease progression and predictors of treatment effectiveness. Although lipids can provide important insight into how diseases initiate and progress, mass spectrometric methods for lipid characterization and profiling are limited due to lipid structural diversity, particularly the presence of various lipid isomers. Moreover, the difficulty of handling small-volume samples exacerbates the intricacies of biological analyses.

Aziridination-Assisted Mass Spectrometry of Nonpolar Sterol Lipids with Isomeric Resolution.

Characterization of nonpolar lipids is crucial due to their essential biological functions and ability to exist in various isomeric forms. In this study, we introduce the N-H aziridination method to target carbon-carbon double bonds (C═C bonds) in nonpolar sterol lipids. The resulting fragments are readily dissociated upon collision-induced dissociation, generating specific fragment ions for C═C bond position determination and fingerprint fragments for backbone characterization.

In situ droplet-based on-tissue chemical derivatization for lipid isomer characterization using LESA.

In this work, we present an in situ droplet-based derivatization method for fast tissue lipid profiling at multiple isomer levels. On-tissue derivatization for isomer characterization was achieved in a droplet delivered by the TriVersa NanoMate LESA pipette. The derivatized lipids were then extracted and analyzed by the automated chip-based liquid extraction surface analysis (LESA) mass spectrometry (MS) followed by tandem MS to produce diagnostic fragment ions to reveal the lipid isomer structures.

Characterization of glycerophospholipids at multiple isomer levels Mn(II)-catalyzed epoxidation.

Characterization of glycerophospholipid isomers is of significant importance as they play different roles in physiological and pathological processes. In this work, we present a novel and bifunctional derivatization method utilizing Mn(II)-catalyzed epoxidation to simultaneously identify carbon-carbon double bond (CC bond)- and stereonumbering ()-positional isomers of phosphatidylcholine. Mn(II) coordinates with picolinic acid and catalyzes epoxidation of unsaturated lipids by peracetic acid.

Lipid Mass Tags via Aziridination for Probing Unsaturated Lipid Isomers and Accurate Relative Quantification.

Knowing concentrations of lipids is essential for understanding their physiological functions and discovering new disease biomarkers. However, it is highly challenging to accurately quantify lipids due to structural diversity and multiple isomeric forms of lipids. To address these critical gaps, we have developed a novel aziridine-based isobaric tag labelling strategy that allows (i) determination of lipid double-bond positional isomers, (ii) accurate relative quantification of unsaturated lipids, and (iii) improvement of ionization efficiencies of nonpolar lipids.

Recent Advances of In-Source Electrochemical Mass Spectrometry.

Hyphenation of electrochemistry (EC) and mass spectrometry has become a powerful tool to study redox processes. Approaches that can achieve this hyphenation include integrating chromatography/electrophoresis between electroinduced redox reactions and detection of products, coupling an EC flow cell to a mass spectrometer, and performing electrochemical reactions inside the ion source of a mass spectrometer. The first two approaches have been well reviewed elsewhere.