Mass Spectrometry Reviews最新文献

The digital ion trap (DIT) is an ion trap in which the periodic trapping field is driven by digital signals-typically with a rectangular waveform-generated by fast-switching circuits. This paper reviews the research history of rectangular wave-driven quadrupole fields, as well as the invention and development of DITs. It summarizes studies on ion motion stability and secular frequency in both 3D and 2D configurations of DITs and discusses differences in the stability diagrams of DITs arising from different definitions of the a and q parameters. Additionally, this review outlines the performance advantages of the digital driving method in mass analysis and lists the novel analytical functions that have been realized using DIT technology. Finally, it presents the latest developments in commercial DIT instruments.

The evolution of nano-electrospray ionization technology began in the mid-1980s. At that time, no commercial vendors supplied the requisite electrospray emitters, which featured internal diameters of just a few microns. Tips were manually fabricated by pulling heated glass capillaries to create micron and sub-micron inside diameter tips. High voltage was applied to a sample solution within the capillary body, and when placed close to a counter electrode of the atmospheric pressure ionization (API) mass spectrometer formed a sufficiently high electric field to produce an electrospray plume. Nano electrospray offered key advantages, including enhanced sensitivity and minimized matrix effects for chemical analysis due to better ionization efficiency and reduced contamination due to the lower mass transfer into the mass spectrometer orifice. By the late 1990s, Advion scientists utilized the Cornell Nanofabrication Facility equipment to create an array of nano-electrospray emitters etched in a silicon wafer. Key to the success of this planar emitter array was the inclusion of a dielectric layer that enabled the formation of an electric field estimated to be equivalent to that of a pulled glass capillary emitter with dimensions near one micron, but with a 28 micron outside diameter emitter. This "ESI Chip" was commercialized along with a robot named NanoMate to enable automated, reproducible, and robust nano electrospray of 96 consecutive samples from the chip-based array of micro-fabricated emitters. This paper explores the development and commercialization story of the NanoMate and its use to expand scientific knowledge in the field of protein non-covalent interactions, protein structure, lipidomics, drug metabolism, and a host of other applications.

Cancer treatment is far from optimal also because current classification systems do not reflect the complex molecular status of the tumor and its phenotype in sufficient detail. To construct molecular tumor classifiers, omics tools provide complex molecular data reflecting many aspects from genotype to phenotype. However, the true molecular effectors in the cells are proteins which often serve as potent cancer biomarkers and therapy targets. This review summarizes the method aspects that allowed the data-independent acquisition (DIA) mass spectrometry (MS) to outperform the traditional, data-dependent acquisition (DDA) approach in recent years. DIA-MS studies have already recapitulated molecular classification of colorectal and breast cancer, provided data improving molecular classification of prostate and other cancers, and led to validated diagnostic, prognostic, predictive biomarkers and therapy targets for common solid tumors. Tissue-specific spectral libraries are important for a deep characterization of tissue proteomes. Further perspectives of current cancer proteomics lie in the fields of single-cell and spatial proteomics and their integration with clinical data. The importance of functional and clinical validation is highlighted to allow stratified and/or personalized targeted therapy.

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has rapidly advanced in biomedical research, enabling label-free, untargeted spatial detection of metabolites, lipids, proteins, and glycans in tissue sections. However, challenges such as low ionization efficiency and chemical instability limit the detection of certain molecules. To address these issues, on-tissue chemical derivatization (OTCD) has been widely applied as an effective strategy to enhance imaging capabilities. This review systematically summarizes the development of derivatization reagents targeting different reactive functional groups and their applications in MALDI-MSI, including strategies for the derivatization of amines, carbonyls, carboxyls, double bonds, hydroxyls, thiols, and platinum-based drugs. Particular attention is given to how these derivatization reagents enhance the detection range and biological relevance by increasing molecular weight, improving ionization efficiency, and reducing background noise interference. Additionally, we explore the application of OTCD in various biological samples and discuss challenges related to experimental workflows, derivatization efficiency, and tissue integrity. This review provides important theoretical support for the advancement of MSI technology and highlights its broad potential applications in biomedical research.

Tannins are widespread specialized plant metabolites that contribute significantly to the polyphenol content of plant-based diets. Their effects on human and animal health vary depending on their structure, with potential benefits including antioxidative, antimicrobial, anthelmintic, and anticarcinogenic properties. Understanding tannin composition and quantity in plant products is essential, as their bioactivities are influenced by their functional groups. Mass spectrometry-based techniques excel in tannin analysis, offering both qualitative and quantitative insights. Combining ultrahigh-performance liquid chromatography with electrospray ionization and high-resolution and triple quadrupole mass analyzers is optimal for comprehensive tannin profiling. Such an approach enables precise analysis and helps predict tannin bioactivities. This review highlights the mass spectrometric analysis of proanthocyanidins and hydrolysable tannins, addressing ionization techniques, interpretation of multiply charged ions, characteristic fragmentations, and reaction monitoring. Applications related to tannin bioactivities are also briefly discussed, demonstrating the utility of mass spectrometry in tannin analysis in complex sample matrices.

Glycosylation, the enzymatic addition of carbohydrate moieties to proteins, is essential for immune recognition, protein folding, and disease progression. The structural complexity of glycans and the heterogeneity of glycosylation sites present significant challenges towards accurate identification and quantification, necessitating advanced methodologies for comprehensive characterization. Tandem MS (MS/MS) has emerged as the primary analytical platform for glycomics and glycoproteomics. This review highlights the recent developments in fragmentation techniques, ranging from well-established techniques such as CID/HCD and ETD, to newer and more advanced techniques such as electron-based methods (EThcD), photodissociation strategies (UVPD, IRMPD), and hybrid approaches (sceHCD, EThcD-sceHCD, HCD-pd-ETD), each providing distinct advantages towards glycan structure elucidation and glycosite mapping. This review also discusses emerging computational strategies, especially deep learning for automated interpretation of complex glycomics and glycoproteomics data.