HX-Eliminierung (X = OH, NH2) aus primären ω-phenylsubstituierten Alkoholen und Aminen: Indiz für interne Solvatisierung von Radikalkationen in der Gasphase oder Resultat einer selektiven Aktivierung von CH-Bindungen? / HX-Elimination (X = OH, NH2) from Primary ω-Phenylsubstituted Alcohols and Amines: a Probe for Internal Solvation of Gaseous Radical Cations or the Result of a Selective Activation of CH-Bonds ?

1977 ◽  
Vol 32 (8) ◽  
pp. 880-885 ◽  
Author(s):  
Karsten Levsen ◽  
Heinz Heimbach ◽  
Michael Bobrich ◽  
Johannes Responder ◽  
Helmut Schwarz
Keyword(s):  
Mass Spectrometry ◽  
Collisional Activation ◽  
Radical Cations ◽  
Selective Activation ◽  
First Time

Using collisional activation mass spectrometry the structures of the [M–HX]+• ions (X = OH, NH2) from 5-phenylpentanol-1 (1), 5-phenylpentylamine (2) and 6-phenylhexanol-1 (3) have been established. Contrary to previous results it is shown for the first time that in addition to ionized 1-phenyl-alkenes-1 some other double bound isomers as well as phenylcyclopentane and phenylcyclohexane are formed. The results strongly suggest that the HX eliminations are induced by a selective activation of CH bonds.

Organische Schwefelverbindungen, XXXIII CO2-Eliminierung aus Radikalkationen von Thiolestern in der Gasphase: Intramolekulare Sauerstoff-Wanderung vom (C+3/C+3)-Typ / Organic Sulfur Compounds, XXXIII CO2 Elimination from Gaseous Radical Cations of Thiol Esters: Intramolecular Oxygen Transfer of (C+3/C+3)-Type

1979 ◽  
Vol 34 (2) ◽  
pp. 316-320 ◽  
Author(s):  
Bernd Kohne ◽  
Klaus Praefcke ◽  
Helmut Schwarz
Keyword(s):  
Gas Phase ◽  
Oxygen Transfer ◽  
Collisional Activation ◽  
Radical Cations ◽  
Ester Group ◽  
Reaction Sequence ◽  
Thiol Ester ◽  
Organic Sulfur Compounds ◽  
Thiol Esters ◽  
First Time

Abstract It is shown for the first time that under electron impact conditions an intramolecular oxygen transfer is possible from the thiol ester funtion onto the carbon atom of a second thiol ester group. The reaction sequence is terminated by CO2 elimination and the proposed structure of the resulting product ion is based on 13 carbon labelling experiments and collisional activation mass spectrometry. In addition, some unusual examples of ring contraction processes in the gas phase are reported.

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

scholarly journals Analysis of Pembrolizumab in Human Plasma by LC-MS/HRMS. Method Validation and Comparison with Elisa

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 621
Author(s):  
Aurélien Millet ◽  
Nihel Khoudour ◽  
Jérôme Guitton ◽  
Dorothée Lebert ◽  
François Goldwasser ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Human Plasma ◽  
High Resolution Mass Spectrometry ◽  
Internal Standard ◽  
Therapeutic Drug ◽  
Limit Of Quantification ◽  
Immunoglobulin G4 ◽  
Positive Mode ◽  
Surrogate Peptide ◽  
First Time

Pembrolizumab is a humanized immunoglobulin G4-kappa anti-PD1 antibody used in the treatment of different solid tumors or haematological malignancies. A liquid chromatography coupled with a high resolution mass spectrometry (orbitrap technology) method was fully developed, optimized, and validated for quantitative analysis of pembrolizumab in human plasma. A mass spectrometry assay was used for the first time a full-length stable isotope-labelled pembrolizumab-like (Arginine 13C6-15N4 and Lysine 13C6-15N2) as an internal standard; the sample preparation was based on albumin depletion and trypsin digestion and, finally, one surrogate peptide was quantified in positive mode. The assay showed good linearity over the range of 1–100 μg/mL, a limit of quantification at 1 μg/mL, excellent accuracy from 4.4% to 5.1%, and also a between-day precision below 20% at the limit of quantification. In parallel, an in-house ELISA was developed with a linearity range from 2.5 to 50 µg/mL. Then, results were obtained from 70 plasma samples of cancer patients that were treated with pembrolizumab and quantified with both methods were compared using the Passing-Bablok regression analysis and Bland-Altman plotting. The LC-MS/HRMS method is easy to implement in the laboratory for use in the context of PK/PD studies, clinical trials, or therapeutic drug monitoring.

scholarly journals Alterations in lipid profile upon uterine fibroids and its recurrence

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Narine M. Tonoyan ◽  
Vitaliy V. Chagovets ◽  
Natalia L. Starodubtseva ◽  
Alisa O. Tokareva ◽  
Konstantin Chingin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Blood Plasma ◽  
Lipid Profile ◽  
Plasma Levels ◽  
Uterine Fibroids ◽  
Control Group ◽  
Cholesterol Esters ◽  
Plasma Samples ◽  
Diagnostic Models ◽  
First Time

AbstractUterine fibroids (UF) is the most common (about 70% cases) type of gynecological disease, with the recurrence rate varying from 11 to 40%. Because UF has no distinct symptomatology and is often asymptomatic, the specific and sensitive diagnosis of UF as well as the assessment for the probability of UF recurrence pose considerable challenge. The aim of this study was to characterize alterations in the lipid profile of tissues associated with the first-time diagnosed UF and recurrent uterine fibroids (RUF) and to explore the potential of mass spectrometry (MS) lipidomics analysis of blood plasma samples for the sensitive and specific determination of UF and RUF with low invasiveness of analysis. MS analysis of lipid levels in the myometrium tissues, fibroids tissues and blood plasma samples was carried out on 66 patients, including 35 patients with first-time diagnosed UF and 31 patients with RUF. The control group consisted of 15 patients who underwent surgical treatment for the intrauterine septum. Fibroids and myometrium tissue samples were analyzed using direct MS approach. Blood plasma samples were analyzed using high performance liquid chromatography hyphened with mass spectrometry (HPLC/MS). MS data were processed by discriminant analysis with projection into latent structures (OPLS-DA). Significant differences were found between the first-time UF, RUF and control group in the levels of lipids involved in the metabolism of glycerophospholipids, sphingolipids, lipids with an ether bond, triglycerides and fatty acids. Significant differences between the control group and the groups with UF and RUF were found in the blood plasma levels of cholesterol esters, triacylglycerols, (lyso) phosphatidylcholines and sphingomyelins. Significant differences between the UF and RUF groups were found in the blood plasma levels of cholesterol esters, phosphotidylcholines, sphingomyelins and triacylglycerols. Diagnostic models based on the selected differential lipids using logistic regression showed sensitivity and specificity of 88% and 86% for the diagnosis of first-time UF and 95% and 79% for RUF, accordingly. This study confirms the involvement of lipids in the pathogenesis of uterine fibroids. A diagnostically significant panel of differential lipid species has been identified for the diagnosis of UF and RUF by low-invasive blood plasma analysis. The developed diagnostic models demonstrated high potential for clinical use and further research in this direction.

scholarly journals Salmonella Typhi and Salmonella Paratyphi A elaborate distinct systemic metabolite signatures during enteric fever

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Elin Näsström ◽  
Nga Tran Vu Thieu ◽  
Sabina Dongol ◽  
Abhilasha Karkey ◽  
Phat Voong Vinh ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Bacterial Infections ◽  
Enteric Fever ◽  
Salmonella Typhi ◽  
Two Dimensional ◽  
Flight Mass Spectrometry ◽  
Metabolite Profiles ◽  
Diagnostic Approaches ◽  
First Time

The host–pathogen interactions induced by Salmonella Typhi and Salmonella Paratyphi A during enteric fever are poorly understood. This knowledge gap, and the human restricted nature of these bacteria, limit our understanding of the disease and impede the development of new diagnostic approaches. To investigate metabolite signals associated with enteric fever we performed two dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC/TOFMS) on plasma from patients with S. Typhi and S. Paratyphi A infections and asymptomatic controls, identifying 695 individual metabolite peaks. Applying supervised pattern recognition, we found highly significant and reproducible metabolite profiles separating S. Typhi cases, S. Paratyphi A cases, and controls, calculating that a combination of six metabolites could accurately define the etiological agent. For the first time we show that reproducible and serovar specific systemic biomarkers can be detected during enteric fever. Our work defines several biologically plausible metabolites that can be used to detect enteric fever, and unlocks the potential of this method in diagnosing other systemic bacterial infections.

scholarly journals Radiocarbon Chronology of the Shigir and Gorbunovo Archaeological Bog Sites, Middle Urals, Russia

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 783-794 ◽  
Author(s):  
Natalia E Zaretskaya ◽  
Sönke Hartz ◽  
Thomas Terberger ◽  
Svetlana N Savchenko ◽  
Mikhail G Zhilin
Keyword(s):  
Mass Spectrometry ◽  
Central And Eastern Europe ◽  
Archaeological Sites ◽  
Peat Bogs ◽  
Middle Urals ◽  
Early Neolithic ◽  
Radiocarbon Chronology ◽  
First Time ◽  
Late Mesolithic ◽  
Ams Dates

Two well-known archaeological sites, the peat bogs of Shigir and Gorbunovo (Middle Urals, Russia), have been radiocarbon dated (61 conventional and accelerator mass spectrometry [AMS] dates from various natural and artifact samples). For the first time, a detailed chronology of Early to Late Mesolithic and Early Neolithic occupation for this region has been obtained, and a paleoenvironmental history reconstructed. Based on these results, we propose that the Mesolithic settlement of the Middle Urals region started in the early Holocene, at the same time as in central and eastern Europe.

Sign in / Sign up

Export Citation Format

Share Document