Focus on field-portable and miniature mass spectrometers. Presentations from the 12th Sanibel Conference on Mass Spectrometry

2001 ◽  
Vol 12 (6) ◽  
pp. 617-618 ◽  
Author(s):  
O. David Sparkman
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometers ◽  
Miniature Mass Spectrometers

scholarly journals Molecular Distributions of Soluble Oxidation Products from Coals Characterized by Mass Spectrometers

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Xing Fan ◽  
Fei Wang
Keyword(s):  
Mass Spectrometry ◽  
Direct Analysis ◽  
Water Soluble ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Mass Spectrometers ◽  
Polycarboxylic Acids ◽  
Alkanoic Acids ◽  
Carboxylic Groups ◽  
Soluble Species

Oxidation of three coals with rank from lignite to anthracite in NaOCl aqueous solution was investigated in this study. The oxidation products were characterized by using gas chromatography/mass spectrometry and direct analysis in real-time mass spectrometry. The results showed that most of organic compounds in coals were converted into water-soluble species under mild conditions, even the anthracite. Benzene polycarboxylic acids (BPCAs) and chloro-substituted alkanoic acids (CSAAs) were major products from the reactions. The products from lower rank coals consist of considerable CSAAs and most products from high rank coals are BPCAs. As coal rank increases, the yield of BPCAs with more carboxylic groups increases.

Recalculations between different expressions of stable HCNOS isotope results – is it easy?

2021 ◽  
Author(s):  
Grzegorz Skrzypek ◽  
Philip Dunn
Keyword(s):  
Mass Spectrometry ◽  
Stable Isotope ◽  
Isotope Ratio ◽  
Data Sets ◽  
Atom Fraction ◽  
Working Standard ◽  
Mass Spectrometers ◽  
User Friendly ◽  
Zero Points ◽  
Selection Of

<p>The stable HCNOS isotope compositions can be reported in various ways depending on scientific domain and needs. The most common notations are 1) the isotope ratio of two stable isotopes; 2) isotope delta value, and 3) atom fraction of one or more of the isotopes. Frequently recalculations between these notations are required for certain applications, particularly when merging different data sets. All these recalculations require using the absolute isotope ratio for the zero points of the stable isotope delta scales (<em>R<sub>std</sub></em>). However, several <em>R<sub>std</sub></em> with very contrasting values have been proposed over time and there is no common agreement on which values should be used word-wide (Skrzypek and Dunn, 2020a).</p><p>Differences in the selection of <em>R<sub>std</sub></em>value may lead to significant differences between different data sets recalculated from delta value to other notations. These differences in R<sub>std</sub> have a significant influence also on the normalization of raw values but only when the normalization is conducted versus the working standard gas value. We proposed a user-friendly EasyIsoCalculator (http://easyisocalculator.gskrzypek.com) that allows recalculation between the main expressions of isotope compositions using various <em>R<sub>std</sub></em> and aids for identification of potential inconsistencies in recalculations (Skrzypek and Dunn, 2020b).</p><p> </p><p>Skrzypek G., Dunn P. 2020a. Absolute isotope ratios defining isotope scales used in isotope ratio mass spectrometers and optical isotope instruments. Rapid Communications in Mass Spectrometry 34: e8890.</p><p>Skrzypek G., Dunn P., 2020b. The recalculation of the stable isotope expressions for HCNOS – EasyIsoCalculator. Rapid Communications in Mass Spectrometry 34: e8892.</p>

scholarly journals In Situ Mass Spectrometry Diagnostics of Impaired Glucose Tolerance Using Label-Free Metabolomic Signature

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1052
Author(s):  
Petr G. Lokhov ◽  
Oxana P. Trifonova ◽  
Dmitry L. Maslov ◽  
Elena E. Balashova
Keyword(s):  
Mass Spectrometry ◽  
Glucose Tolerance ◽  
Data Processing ◽  
Impaired Glucose Tolerance ◽  
Characteristic Curve ◽  
Complex Data ◽  
Label Free ◽  
Mass Peak ◽  
Mass Spectrometers

In metabolomics, mass spectrometry is used to detect a large number of low-molecular substances in a single analysis. Such a capacity could have direct application in disease diagnostics. However, it is challenging because of the analysis complexity, and the search for a way to simplify it while maintaining the diagnostic capability is an urgent task. It has been proposed to use the metabolomic signature without complex data processing (mass peak detection, alignment, normalization, and identification of substances, as well as any complex statistical analysis) to make the analysis more simple and rapid. Methods: A label-free approach was implemented in the metabolomic signature, which makes the measurement of the actual or conditional concentrations unnecessary, uses only mass peak relations, and minimizes mass spectra processing. The approach was tested on the diagnosis of impaired glucose tolerance (IGT). Results: The label-free metabolic signature demonstrated a diagnostic accuracy for IGT equal to 88% (specificity 85%, sensitivity 90%, and area under receiver operating characteristic curve (AUC) of 0.91), which is considered to be a good quality for diagnostics. Conclusions: It is possible to compile label-free signatures for diseases that allow for diagnosing the disease in situ, i.e., right at the mass spectrometer without complex data processing. This achievement makes all mass spectrometers potentially versatile diagnostic devices and accelerates the introduction of metabolomics into medicine.

MASS SPECTRA AND DISSOCIATION PATTERNS OF TELLURIUM CLUSTERS USING POSITIVE AND NEGATIVE SECONDARY-ION MASS SPECTROMETRY

1996 ◽  
Vol 03 (01) ◽  
pp. 577-582 ◽  
Author(s):  
H. ITO ◽  
T. SAKURAI ◽  
T. MATSUO ◽  
T. ICHIHARA ◽  
I. KATAKUSE
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Cluster Ions ◽  
Mass Spectrometers ◽  
Scanning Method ◽  
Ion Mass Spectrometry ◽  
Cluster Ion ◽  
Sector Type ◽  
Fragmentation Patterns ◽  
Secondary Ion

Size distribution of positive and negative tellurium clusters in the size range from 2 to 56 atoms was investigated by secondary-ion mass spectrometry (SIMS). Cluster ions were produced by the 12-keV Xe+ ions bombardment of a sample tellurium sheet and were mass-analyzed using sector-type double-focusing mass spectrometers. It was found that a discontinuous variation of cluster-ion intensity appeared at specific numbers of n. These numbers were 5, 8, 12, 15, 19, and 23 for positive clusters and 6, 10, 13, and 16 for negative clusters. The dissociation pattern was also investigated by an acceleration-voltage scanning method. It was found that Te2, Te5, and Te6 fragmentation events occurred at a large probability. Observation of specific fragmentation patterns suggested the existence of nonsequential fragment channels.

scholarly journals Mass spectrometry: From plasma proteins to mitochondrial membranes

2019 ◽  
Vol 116 (8) ◽  
pp. 2814-2820 ◽  
Author(s):  
Carol V. Robinson
Keyword(s):  
Mass Spectrometry ◽  
Cell Biology ◽  
Protein Complexes ◽  
Intact Protein ◽  
Exchange Reactions ◽  
Soft Landing ◽  
Mass Spectrometers ◽  
Radical Method ◽  
Key Steps ◽  
Soluble Complexes

In this Inaugural Article, I trace some key steps that have enabled the development of mass spectrometry for the study of intact protein complexes from a variety of cellular environments. Beginning with the preservation of the first soluble complexes from plasma, I describe our early experiments that capitalize on the heterogeneity of subunit composition during assembly and exchange reactions. During these investigations, we observed many assemblies and intermediates with different subunit stoichiometries, and were keen to ascertain whether or not their overall topology was preserved in the mass spectrometer. Adapting ion mobility and soft-landing methodologies, we showed how ring-shaped complexes could survive the phase transition. The next logical progression from soluble complexes was to membrane protein assemblies but this was not straightforward. We encountered many pitfalls along the way, largely due to the use of detergent micelles to protect and stabilize complexes. Further obstacles presented when we attempted to distinguish lipids that copurify from those that are important for function. Developing new experimental protocols, we have subsequently defined lipids that change protein conformation, mediate oligomeric states, and facilitate downstream coupling of G protein-coupled receptors. Very recently, using a radical method—ejecting protein complexes directly from native membranes into mass spectrometers—we provided insights into associations within membranes and mitochondria. Together, these developments suggest the beginnings of mass spectrometry meeting with cell biology.

scholarly journals Quantitative mass spectrometry: an overview

2016 ◽  
Vol 374 (2079) ◽  
pp. 20150382 ◽  
Author(s):  
Pawel L. Urban
Keyword(s):  
Mass Spectrometry ◽  
Chemical Analysis ◽  
First Century ◽  
Quantitative Mass Spectrometry ◽  
Theme Issue ◽  
Direct Identification ◽  
Mass Spectrometers ◽  
Analysis Technique ◽  
Chemical Analysis Technique ◽  
Fragmentation Patterns

Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry—especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements. This article is part of the themed issue ‘Quantitative mass spectrometry’.

scholarly journals Steroid Hormone Analysis by Tandem Mass Spectrometry

2009 ◽  
Vol 55 (6) ◽  
pp. 1061-1066 ◽  
Author(s):  
Steven J Soldin ◽  
Offie P Soldin
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
High Performance ◽  
Tandem Mass ◽  
Mass Spectrometers ◽  
Liquid Chromatography Tandem Mass ◽  
Steroid Profiles ◽  
Diagnostic Capabilities ◽  
New Applications

Abstract Background: New high-performance liquid chromatography/tandem mass spectrometry (LC-MS/MS) methods are among the most successful approaches to improve specificity problems inherent in many immunoassays. Content: We emphasize problems with immunoassays for the measurement of steroids and review the emerging role of LC-MS/MS in the measurement of clinically relevant steroids. The latest generation of tandem mass spectrometers has superior limits of quantification, permitting omission of previously employed derivatization steps. The measurement of steroid profiles in the diagnosis and treatment of congenital adrenal hyperplasia, adrenal insufficiency, chronic pelvic pain and prostatitis, oncology (breast cancer), and athletes has important new applications. Conclusions: LC-MS/MS now affords the specificity, imprecision, and limits of quantification necessary for the reliable measurement of steroids in human fluids, enhancing diagnostic capabilities, particularly when steroid profiles are available.

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