Mass Spectrometry Reviews最新文献

The review examines the evolution of chemical ionization mass spectrometry (CI-MS), a technique developed in 1966 by Field and Munson. CI is a soft-ionization method that produces more intense molecular ions with less fragmentation than electron ionization (EI). CI-MS is widely utilized across various fields, including atmospheric chemistry, environmental science, and biomedical research. The article highlights different CI-MS types, such as proton transfer reaction mass spectrometry (PTR-MS), which is renowned for its ability to analyze volatile organic compounds in real-time; negative ion CI-MS, which provides insights into anions; selected ion flow tube mass spectrometry (SIFT-MS), and ion-drift chemical ionization mass spectrometry (ID-CIMS), techniques that allow for the direct analysis of trace gases with high sensitivity and specificity. The article discusses advancements in chromatography with CI-MS, particularly atmospheric pressure chemical ionization (APCI) and liquid electron ionization (LEI) interface. The ongoing exchange of data between fundamental ion/molecule studies and specific applications has significantly boosted the growth of CI-MS in recent decades. In recent years, no extensive review has been published on CI-MS. This article provides an overview of CI-MS technique, its applications, and its evolution over the years, highlighting its importance in advancing scientific research and understanding the chemistry of various environments.

Because matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) induces selective cleavage on the peptide backbone, this technique allows reliable identification of peptides and proteins. In the last 15 years, several new matrices have been developed that more efficiently induce MALDI-ISD, opening new research avenues. Fragmentation of peptides by MALDI-ISD can be divided into two categories: reducing and oxidizing matrices induce selective cleavage of N-Cα and Cα-C bonds, respectively. Regarding the dissociation mechanism, MALDI-ISD was believed, until recently, to be initiated by "hydrogen atom" transfer between an analyte peptide and the matrix. Based on this hypothesis, the origin of the hydrogen atoms would be the aniline group of the matrix in MALDI with a reducing matrix and the amide nitrogen of the peptide backbone in MALDI-ISD with an oxidizing matrix. MALDI-ISD involves homolytic cleavage of N-H bonds, though the N-H bond is generally stronger than O-H and C-H bonds. Notably, mass spectrometry experiments cannot distinguish between "hydrogen atom transfer" and "electron transfer and subsequent proton transfer." Recent well-designed experiments and quantum chemistry calculations have strongly suggested that electron transfer between the peptide and matrix is likely to be the initial step of the MALDI-ISD process. Reducing and oxidizing matrices for MALDI-ISD induce fragmentation through peptide radical anions and cations, respectively. The generated fragment ions and radicals subsequently undergo reactions within the MALDI plume, leading to the formation of stable even-electron ions that are detectable in the mass spectrum. As a result, MALDI-ISD fragments are observed as both positively and negatively charged ions, despite MALDI-ISD entailing the fragmentation of peptide radical anions and cations. The proposed mechanism offers a robust framework for understanding the MALDI-ISD process. A more comprehensive understanding of this process is essential to fully harness the potential of the MALDI-ISD technique and would pave the way for further development of methodologies advancing the field of analytical chemistry based on finding new matrices.

Phytocannabinoids are bioactive metabolites derived from the Cannabis sativa plant. They have garnered attention due to their recreational uses and therapeutic potential. Although various analytical strategies have been employed for their analysis, mass spectrometry (MS) coupled to chromatographic separation is superior due to its sensitivity and selectivity. Various MS-based strategies, namely Gas chromatography (GC-MS) and liquid chromatography - MS (LC-MS) are reviewed with focus on the analysis of phytocannabinoids in vascular matrices. These include plasma, serum, whole blood, and dried blood spots (DBS). Applications, advantages and challenges associated with each MS strategy in vascular matrices are evaluated and critically discussed. In addition, the review outlines the challenges in DBS spot analysis, such as hematocrit bias, versus plasma/serum and whole blood processing, which involves protein removal, extraction and cleanup steps.

Mass spectrometry (MS) is a widely recognized analytical technique that can be applied to both large and small molecules and is a potent analytical tool that advances both basic science and practical applications in and out of the lab. MS has become a desirable analytical technique in clinical and bioanalytical labs with its high sensitivity, broad applicability, and throughput benefits. Numerous MS approaches, combined with various separation methods including gas and liquid chromatography, have been proposed to examine intricate matrices. Nevertheless, this technique could be limited by the labor-intensive and drawn-out sample preparation needed before MS analysis. By enabling the direct MS analysis of complex materials under ambient settings with little to no sample pretreatment, AIMS has cut down on both analysis time and expense. Nonetheless, these methods' speed and simplicity make them appropriate for use in critical care and point-of-care testing. Because of this, ambient ionization mass spectrometry (AIMS) has inevitably appealed to a wide range of scientists. The field of AIMS has grown tremendously since its foundation in the mid-2000s, marked by the emergence of numerous new ion sources, a plethora of fascinating applications, and a discernible increase in interest from various fields of study. Around the world, ambient ionization techniques are becoming more and more widespread in laboratories as the science advances yearly. This review focuses on the recent bioanalytical applications of AIMS in fields such as clinics, drugs, forensics, food, and environment, with a specific emphasis on the research reported in manuscripts published during the last 5 years. Although certain methodological developments are mentioned in this review, its primary goal is to demonstrate the practical applications of AIMS in bioanalytical fields. A timely overview of AIMS-based procedures and their application in various sample situations is what this endeavor seeks to give bioanalytical researchers. Moreover, several cutting-edge biological applications have been highlighted to explain how the AIMS area can develop in the future. In this chapter, readers will be provided with a quick overview of the main AIMS methodologies and their recent applied use cases.

This review highlights advancements in mass spectrometry (MS)-based glycomics in food and nutritional science. Carbohydrates, which are vital for human health, exhibit complex structures, making their analysis challenging. MS has become an indispensable tool for elucidating the structures of carbohydrates, including glycans, through soft ionization techniques such as MALDI and ESI. Furthermore, coupling MS with advanced separation techniques enhances sensitivity and resolution. This review underscores the pivotal contributions of Professor Carlito B. Lebrilla to glycomics research, particularly regarding milk oligosaccharides and dietary fibers, and their roles in gut health. Comprehensive food glycomic databases and MS-based studies offer valuable insights into the functions of carbohydrates and their implications for nutrition.

I recall the day when Laurence Charles and Richard Cole approached me to be a guest editor for a special issue honoring the life work of my former PhD adviser and friend, Distinguished Professor Chrys Wesdemiotis, at The University of Akron. It took me less than one second to say I would be honored to participate because of how Chrys made an impact, not just on my life, but for the countless others who have worked with him over the years. Many of us know Chrys for his vast scientific achievements, crossing multi-disciplinary fields of research. However, only a select group of his former students and postdocs can truly appreciate Chrys and his impact on our lives throughout the years. Chrys has been an integral part of celebrating our successes in the lab, mentoring us through challenging times, and being part of our lives even well beyond our studies and research on campus. In this reminiscence article, a group of former and current students will comment on how Chrys is special to us, and we genuinely appreciate him being our adviser, mentor, and friend. We are thrilled to see Chrys being honored with this special issue of Mass Spectrometry Reviews!

Bryan Katzenmeyer, PhD

Director, Mass Spectrometry Business at JEOL

Ambient and direct mass spectrometry (MS) methods are becoming increasingly used for the rapid analysis of food, beverage and agricultural samples. Novel ionization approaches combined with targeted, or untargeted workflows provide analytical outcomes within a greatly reduced time period compared to traditional separation science coupled with MS detection. This review will provide an overview of atmospheric pressure ionization MS based techniques for analysis of food, beverage and agricultural samples, with an emphasis on direct and rapid analysis including ambient ionization. The review will be completed through presentation of relevant examples of the use of ambient ionization techniques for food and beverage analysis along with the authors perspectives for future challenges relevant to the field.

Glycosylation is an abundant post-translational modification that impacts a wide variety of functions, including protein regulation, cell adhesion, and structural integrity. The application of proteomics methods to glycopeptide assignment faces unique challenges due to high heterogeneity, which results in complex populations with low overall abundance per glycopeptide. In addition, glycans dissociate at a lower collision energy compared to their attached peptide component. The resulting mass spectral data require specialized assignment software, which has caused glycoproteomics to lag traditional proteomics. Existing software primarily focuses on data-dependent acquisition (DDA), but manual validation is frequently required, and experiments are necessarily limited by the stochastic nature of DDA ion-selection. Data-independent acquisition (DIA) allows for a more complete and robust analysis of glycopeptide samples, but analysis software is still sparse. In this review, we discuss the current state of DDA analysis software, the limitations, and how it can inform our forays into DIA glycoproteomics.

Interactions between glycan-binding proteins (GBPs) and carbohydrates (glycans) are essential to many biological processes relevant to human health and disease. For most GBPs, however, their glycan interactome-the repertoire of glycans recognized and their specificities-is poorly defined. The structural diversity of biologically relevant glycans and their limited availability in purified form, as well as their varied presentation, often as glycoconjugates, and weak affinities are key challenges hindering comprehensive glycan interaction mapping. Native mass spectrometry (nMS), a versatile, sensitive and label-free tool for the discovery of GBP-glycan interactions and quantifying their stoichiometry and thermodynamic parameters, is poised to play a leading role in defining the glycan interactome of GBPs. Here, we review established nMS methodologies, as well as important experimental and instrumental considerations, for detecting GBP-glycan interactions in vitro, and reliably measuring their stoichiometry and affinity. Recent advances in nMS methods for high-throughput library screening, including shotgun glycomics, and quantifying GBP interactions with glycoproteins and glycosphingolipids, are also described.

Histone proteins and their posttranslational modifications are central to chromatin structure and function. These modifications often occur in combinations, generating a diverse array of histone proteoforms that contribute to the dynamic regulation of chromatin architecture. Advancements in mass spectrometry-based proteomics, particularly top-down and middle-down approaches, have significantly enhanced our ability to characterize these proteoforms and elucidate PTM crosstalk. This review provides an analysis of the epigenetic machinery involved in the addition, recognition, and removal of histone PTMs, emphasizing the complexity introduced by histone variants and combinatorial PTM patterns. We examine the challenges and limitations of traditional antibody-based methods for PTM analysis and highlight the advantages of mass spectrometry techniques in providing comprehensive and quantitative insights into histone proteoforms. Key considerations in experimental design, sample preparation, chromatographic separation, and data analysis are outlined for the effective application of mass spectrometry for histone proteoform studies. By integrating these technological advancements on the side of sample preparation, instrumentation, and data processing a deeper understanding of chromatin regulation through PTM crosstalk is achieved, paving the way for mass spectrometry-based proteomics to spearhead the discovery of novel therapeutic strategies with proteoform level specificity.