An astonishingly simple new method to produce gas-phase ions of small molecules as well as proteins from the solid state under cold vacuum conditions is described. This matrix assisted ionization vacuum (MAIV) mass spectrometry (MS) method produces multiply charged ions similar to those that typify electrospray ionization (ESI) and uses sample preparation methods that are nearly identical to matrix-assisted laser desorption/ionization (MALDI). Unlike these established methods, MAIV does not require a laser or voltage for ionization, and unlike the recently introduced matrix assisted ionization inlet method, does not require added heat. MAIV-MS requires only introduction of a crystalline mixture of the analyte incorporated with a suitable small molecule matrix compound such as 3-nitrobenzonitrile directly to the vacuum of the mass spectrometer. Vacuum intermediate pressure MALDI sources and modified ESI sources successfully produce ions for analysis by MS with this method. As in ESI-MS, ion formation is continuous and, without a laser, little chemical background is observed. MAIV, operating from a surface offers the possibility of significantly improved sensitivity relative to atmospheric pressure ionization because ions are produced in the vacuum region of the mass spectrometer eliminating losses associated with ion transfer from atmospheric pressure to vacuum. Mechanistic aspects and potential applications for this new ionization method are discussed.
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http://dx.doi.org/10.1007/s13361-012-0571-z | DOI Listing |
NPJ Vaccines
January 2025
Department of Biochemistry, University of Oxford, OX1 3QU, Oxford, UK.
The rapid development and worldwide distribution of COVID-19 vaccines is a remarkable achievement of biomedical research and logistical implementation. However, these developments are associated with the risk of a surge of substandard and falsified (SF) vaccines, as illustrated by the 184 incidents with SF and diverted COVID-19 vaccines which have been reported during the pandemic in 48 countries, with a paucity of methods for their detection in supply chains. In this context, matrix-assisted laser desorption ionisation-time of flight (MALDI-ToF) mass spectrometry (MS) is globally available for fast and accurate analysis of bacteria in patient samples, offering a potentially accessible solution to identify SF vaccines.
View Article and Find Full Text PDFEnviron Int
January 2025
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Carbon Neutrality Interdisciplinary Science Centre, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Data-driven approaches (e.g., machine learning) are increasingly used to replace or assist laboratory studies in the study of emerging contaminants (ECs).
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Department of Chemistry & Institute for Sustainable Energy, College of Sciences, Shanghai University, Shanghai 200444, PR China. Electronic address:
Heteroatom doping into the transition metal-based catalysts is an effective strategy to improve the oxygen reduction reaction (ORR) kinetics. Herein, we proposed a one-step, soft template assisted, and green method for the synthesis of Sulfur (S) doped single atom FeNC catalyst. XAFS demonstrated that the Fe active sites in the FeNSC were more likely to possess the Fe-N configuration.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
A novel ionic liquid MALDI matrix, 3-aminoquinoline/2',4',6'-trihydroxyacetophenone monohydrate (3-AQ/THAP), was developed for the rapid qualitative and quantitative detection of miRNA from biological samples. Compared to the traditional matrix 2,5-dihydroxybenzoic acid (DHB) and previously reported oligonucleotide-specific matrices, such as 3-aminopicolinic acid (3-APA), 3-hydroxypicolinic acid (3-HPA), and 6-aza-2-thiothymine (ATT), the 3-AQ/THAP matrix offers several advantages. It produces fewer alkali metal adduct peaks, exhibits higher sensitivity, and ensures better spot-to-spot repeatability.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Chemistry, Faculty of Science, Masaryk University, Brno 625 00, Czech Republic.
Obtaining high-quality matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) images and the reproducibility of the technique depend strongly on the sample preparation protocol. The most crucial part is the application of the MALDI matrix, which often relies on expensive spraying or sublimation coaters. In this work, we present a new dual-polarity matrix for MALDI mass spectrometry imaging (MSI): Basic Blue 7 (BB7), which belongs to the group of triarylmethane dyes.
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