Localization of malonyl and acetyl on substituted saikosaponins according to the full‐scan mass spectra and the fragmentation of sodium‐adduct ions in the positive mode

2019 ◽  
Vol 33 (9) ◽  
pp. 883-893 ◽  
Author(s):  
Guoqiang Liu ◽  
Zunjian Zhang ◽  
Xiaoqing Lv ◽  
Shuyu Zhan ◽  
Baoue Ding ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Sodium Adduct ◽  
Positive Mode ◽  
Full Scan

A Fast and Sensitive Method Combining Reversed-Phase Chromatography with High Resolution Mass Spectrometry to Quantify 2-Fluoro-2-Deoxyglucose and Its Phosphorylated Metabolite for Determining Glucose Uptake

2019 ◽  
Author(s):  
Ashley Williams ◽  
Deborah Muoio ◽  
Guofang Zhang
Keyword(s):  
Glucose Uptake ◽  
Biological Samples ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Sodium Adduct ◽  
Negative Mode ◽  
Glucose Analogues ◽  
Positive Mode ◽  
Q Exactive ◽  
Glucose Analogue

Quantative measurements of the glucose analogue, 2-deoxyglucose (2DG), and its phosphorylated metabolite (2-deoxyglucose-6-phosphate (2DG-6-P)) are critical for the measurement of glucose uptake. While the field has long identified the need for sensitive and reliable assays that deploy non-radiolabled glucose analogues to assess glucose uptake, no analytical MS-based methods exist to detect trace amounts in complex biological samples. In the present work, we show that 2DG is poorly suited for MS-based methods due to interfering metabolites. We therefore developed and validated an alternative C18-based LC-Q-Exactive-Orbitrap-MS method using 2-fluoro-2-deoxyglucose (2FDG) to quantify both 2FDG and 2FDG-6-P by measuring the sodium adduct of 2FDG in the positive mode and deprotonation of 2FDG-6-P in the negative mode. The low detection limit of this method can reach 81.4 and 48.8 fmol for both 2FDG and 2FDG-6-P, respectively. The newly developed method was fully validated via calibration curves in the presence and absence of biological matrix. The present work is the first successful LC-MS method that can quantify trace amounts of a nonradiolabeled glucose analogue and its phosphorylated metabolite and is a promising analytical method to determine glucose uptake in biological samples.

Unexpected cytosine–AuCl4− interaction under electrospray ionization mass spectrometry conditions—Formation of cytosine–Au(I) complexes

2019 ◽  
Vol 26 (3) ◽  
pp. 225-229
Author(s):  
Magdalena Frańska ◽  
Emilia Konował
Keyword(s):  
Electrospray Ionization ◽  
Gas Phase ◽  
Mass Spectra ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Ionization Mass ◽  
Ionization Source ◽  
Full Scan ◽  
Negative Ion Mode ◽  
Product Ion Spectra

The interaction of cytosine with AuCl4−, under electrospray ionization mass spectrometric conditions, is discussed. On the basis of respective full scan mass spectra and product ion spectra, obtained in positive and negative ion mode, it has been deduced that cytosine is very prone to form Au(I)-containing complexes. The complexes may be formed in the gas phase by decomposition of Au(III)-containing complexes and also in the electrospray ionization source as a result of the occurrence of redox process. It has also been found that the interaction of cytosine with Au+ is stronger than that with Cu+ or Ag+, although taking into account the electrostatic attraction, it is not expected.

A Fast and Sensitive Method Combining Reversed-Phase Chromatography with High Resolution Mass Spectrometry to Quantify 2-Fluoro-2-Deoxyglucose and Its Phosphorylated Metabolite for Determining Glucose Uptake

2019 ◽  
Author(s):  
Ashley Williams ◽  
Deborah Muoio ◽  
Guofang Zhang
Keyword(s):  
Glucose Uptake ◽  
Biological Samples ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Sodium Adduct ◽  
Negative Mode ◽  
Glucose Analogues ◽  
Positive Mode ◽  
Q Exactive ◽  
Glucose Analogue

Quantative measurements of the glucose analogue, 2-deoxyglucose (2DG), and its phosphorylated metabolite (2-deoxyglucose-6-phosphate (2DG-6-P)) are critical for the measurement of glucose uptake. While the field has long identified the need for sensitive and reliable assays that deploy non-radiolabled glucose analogues to assess glucose uptake, no analytical MS-based methods exist to detect trace amounts in complex biological samples. In the present work, we show that 2DG is poorly suited for MS-based methods due to interfering metabolites. We therefore developed and validated an alternative C18-based LC-Q-Exactive-Orbitrap-MS method using 2-fluoro-2-deoxyglucose (2FDG) to quantify both 2FDG and 2FDG-6-P by measuring the sodium adduct of 2FDG in the positive mode and deprotonation of 2FDG-6-P in the negative mode. The low detection limit of this method can reach 81.4 and 48.8 fmol for both 2FDG and 2FDG-6-P, respectively. The newly developed method was fully validated via calibration curves in the presence and absence of biological matrix. The present work is the first successful LC-MS method that can quantify trace amounts of a nonradiolabeled glucose analogue and its phosphorylated metabolite and is a promising analytical method to determine glucose uptake in biological samples.

Tandem Mass Spectrometry Characteristics of Polyester Anions and Cations Formed by Electrospray Ionization

2005 ◽  
Vol 11 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Mark A. Arnould ◽  
Rafael Vargas ◽  
Rita W. Buehner ◽  
Chrys Wesdemiotis
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
Mass Spectra ◽  
Quadrupole Ion Trap ◽  
Tandem Mass ◽  
Negative Mode ◽  
End Groups ◽  
Positive Mode ◽  
End Group

Electrospray ionization of polyesters composed of isophthalic acid and neopentyl glycol produces carboxylate anions in negative mode and mainly sodium ion adducts in positive mode. A tandem mass spectrometry (MS/MS) study of these ions in a quadrupole ion trap shows that the collisionally-activated dissociation pathways of the anions are simpler than those of the corresponding cations. Charge-remote fragmentations predominate in both cases, but the spectra obtained in negative mode are devoid of the complicating cation exchange observed in positive mode. MS/MS of the Na+ adducts gives rise to a greater number of fragments but not necessarily more structural information. In either positive or negative mode, polyester oligomers with different end groups fragment by similar mechanisms. The observed fragments are consistent with rearrangements initiated by the end groups. Single-stage ESI mass spectra are also more complex in positive mode because of extensive H/Na substitutions; this is also true for matrix-assisted laser desorption ionization mass spectra. Hence, formation and analysis of anions might be the method of choice for determining block length, end group structure and copolymer sequence, provided the polyester contains at least one carboxylic acid end group that is ionizable to anions.

scholarly journals Artemisia annua Growing Wild in Romania—A Metabolite Profile Approach to Target a Drug Delivery System Based on Magnetite Nanoparticles

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2245
Author(s):  
Adina-Elena Segneanu ◽  
Catalin Nicolae Marin ◽  
Ioan Ovidiu-Florin Ghirlea ◽  
Catalin Vladut Ionut Feier ◽  
Cornelia Muntean ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Artemisia Annua ◽  
Metabolite Profile ◽  
Ecological Environment ◽  
Carrier System ◽  
Isolation And Purification ◽  
Positive Mode ◽  
Purification Stage ◽  
Profile Approach ◽  
Carrier Systems

The metabolites profile of a plant is greatly influenced by geographical factors and the ecological environment. Various studies focused on artemisinin and its derivates for their antiparasitic and antitumoral effects. However, after the isolation and purification stage, their pharmaceutical potential is limited due to their low bioavailability, permeability and lifetime. The antibacterial activity of essential oils has been another topic of interest for many studies on this plant. Nevertheless, only a few studies investigate other metabolites in Artemisia annua. Considering that secondary metabolites act synergistically in a plant, the existence of other metabolites with antitumor and high immunomodulating activity is even more important. Novel nano-carrier systems obtained by loading herbs into magnetic nanoparticles ensures the increase in the antitumor effect, but also, overcoming the barriers related to permeability, localization. This study reported the first complete metabolic profile from wild grown Romanian Artemisia annua. A total of 103 metabolites were identified under mass spectra (MS) positive mode from 13 secondary metabolite categories: amino acids, terpenoids, steroids, coumarins, flavonoids, organic acids, fatty acids, phenolic acids, carbohydrates, glycosides, aldehydes, hydrocarbons, etc. In addition, the biological activity of each class of metabolites was discussed. We further developed a simple and inexpensive nano-carrier system with the intention to capitalize on the beneficial properties of both components. Evaluation of the nano-carrier system’s morpho-structural and magnetic properties was performed.

Analysis of thermolabile and polar pesticides in environmental water with capillary chromatography-frit-fast atom bombardment mass spectrometry

1998 ◽  
Vol 38 (7) ◽  
pp. 169-177 ◽  
Author(s):  
Jian-ying Hu ◽  
Takako Aizawa ◽  
Mari Asami ◽  
Yasumoto Magara
Keyword(s):  
Mobile Phase ◽  
Solid Phase ◽  
High Sensitivity ◽  
Environmental Water ◽  
Selected Ion Monitoring ◽  
Polar Pesticides ◽  
Positive Mode ◽  
Full Scan ◽  
Acidic Pesticides

Capillary LC/Frit-FAB-MS was used for the determination of 24 thermolabile and polar pesticides including 9 neutral/basic and 15 acidic ones which are not amenable to routine GC/MS. The base ions of acidic pesticides in negative mode were a deprotonated molecular ion except for asulam, MCPB, 2,4-DB, and warfarin, and those for neutral/basic pesticides and asulam in positive mode were a protonated one. More than one diagnostic ion were obtained except for hymexazol and bentazone. High sensitivity was obtained for neutral/basic pesticides and asulam by adopting a mobile phase composed of CH3CN and 0.1% acetic acid, while for the other acidic pesticides, a mobile phase composed of CH3CN and 5 mM din-butylammonium acetate (pH=6.7) was effective. The detection limits of the pesticides were in the range of 10∼300 μg/l, except for benazolin whose limit was 1000 μg/l. Environmental samples (1 L) were taken from raw water for water supply and applied to analysis after concentration by using a solid phase extraction method. 0.2 μg/l dymron (in full-scan mode) and 0.05 μ/l 2,4-D (in selected ion monitoring mode) were detected in a sample, which indicated that the LC-frit-FAB-MS method could be used for determining thermolabile and polar pesticides in environmental water with relatively high sensitivity.

scholarly journals COSIMA data analysis using multivariate techniques

2015 ◽  
Vol 4 (1) ◽  
pp. 45-56 ◽  
Author(s):  
J. Silén ◽  
H. Cottin ◽  
M. Hilchenbach ◽  
J. Kissel ◽  
H. Lehto ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Secondary Ion Mass Spectrometry ◽  
Random Projections ◽  
Multivariate Techniques ◽  
Positive Mode ◽  
Clustering And Classification ◽  
Qualitative Similarity ◽  
Secondary Ion ◽  
Measured Mass

Abstract. We describe how to use multivariate analysis of complex TOF-SIMS (time-of-flight secondary ion mass spectrometry) spectra by introducing the method of random projections. The technique allows us to do full clustering and classification of the measured mass spectra. In this paper we use the tool for classification purposes. The presentation describes calibration experiments of 19 minerals on Ag and Au substrates using positive mode ion spectra. The discrimination between individual minerals gives a cross-validation Cohen κ for classification of typically about 80%. We intend to use the method as a fast tool to deduce a qualitative similarity of measurements.

scholarly journals COSIMA data analysis using multivariate techniques

2014 ◽  
Vol 4 (2) ◽  
pp. 455-489 ◽  
Author(s):  
J. Silén ◽  
H. Cottin ◽  
M. Hilchenbach ◽  
J. Kissel ◽  
H. Lehto ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Mass Spectra ◽  
Random Projections ◽  
Multivariate Techniques ◽  
Tof Sims ◽  
Positive Mode ◽  
Clustering And Classification ◽  
Qualitative Similarity ◽  
Measured Mass

Abstract. We describe how to use multivariate analysis of complex TOF-SIMS spectra introducing the method of random projections. The technique allows us to do full clustering and classification of the measured mass spectra. In this paper we use the tool for classification purposes. The presentation describes calibration experiments of 19 minerals on Ag and Au substrates using positive mode ion spectra. The discrimination between individual minerals gives a crossvalidation Cohen κ for classification of typically about 80%. We intend to use the method as a fast tool to deduce a qualitative similarity of measurements.

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