Isomeric effect on the mass spectrometric dissociation of aglycones of saikosaponins in the negative ion mode

2020 ◽  
Vol 34 (14) ◽  
Author(s):  
Guoqiang Liu ◽  
Zunjian Zhang ◽  
Xinji Yang ◽  
Shuyu Zhan ◽  
Xiaoqing Lv ◽  
...  
Keyword(s):  
Mass Spectrometric ◽  
Negative Ion ◽  
Isomeric Effect ◽  
Negative Ion Mode

Confounding contaminants in mass spectrometric reaction monitoring

2018 ◽  
Author(s):  
Gilian T. Thomas ◽  
Landon MacGillivray ◽  
Natalie L. Dean ◽  
Rhonda L. Stoddard ◽  
Lars Yunker ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Reaction Monitoring ◽  
Schlenk Flask ◽  
Dynamic Analyses ◽  
Rubber Septa ◽  
Negative Ion Mode ◽  
Mode A

<p>Reactions carried out in the presence of rubber septa run the risk of additives being leached out by the solvent. Normally, such species are present at low enough levels that they do not interfere with the reaction significantly. However, when studying reactions using sensitive methods such as mass spectrometry, the appearance of even trace amounts of material can confuse dynamic analyses of reactions. A wide variety of additives are present in rubber along with the polymer: antioxidants, dyes, detergent, and vulcanization agents, and these are all especially problematic in negative ion mode. A redesigned Schlenk flask for pressurized sample infusion (PSI) is presented as a means of practically eliminating the presence of contaminants during reaction analyses.</p>

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.

Determination of Tobacco Specific Hemoglobin Adducts in Smoking Mothers and New Born Babies by Mass Spectrometry

2007 ◽  
Vol 2 ◽  
pp. 117727190700200 ◽  
Author(s):  
Steven R. Myers ◽  
Yeakub Ali
Keyword(s):  
Mass Spectrometry ◽  
Biological Markers ◽  
Chemical Ionization ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectrometric Analysis ◽  
Hemoglobin Adducts ◽  
Environmental Carcinogens ◽  
Negative Ion Mode

Biological markers for assessment of exposure to a variety of environmental carcinogens has been widely applied in both basic as well as clinical research. Exposure to tobacco smoke presents an ideal environment with which to develop, characterize, and refine biological markers, especially of those carcinogens found in tobacco. In the present study, a sensitive gas chromatography/mass spectrometry (GC/MS) method was developed to measure nitrosamine- hemoglobin adducts (HPB-Hb (4-Hydroxy-3-pyridinyl-1-butanone) at trace levels in red blood cells of both African-American and Caucasian smoking and nonsmoking mothers and their infants. Gas chromatographic and mass spectrometric methods with chemical ionization (CI) of methane reagent gas in both positive and negative ion mode as well as electron ionization (EI) were studied to determine differences in sensitivity of detection among the various ionization methods. Detection limits using both positive and negative chemical ionization modes were found to be 30 femtomoles of HPB, whereas detection using electron impact modes yielded a detection limit of 80 femtomoles of HBP. Comparative derivatization of HPB was performed using O-bis(Trimethylsilyl)-trifluoroacetamide (BSTFA) and 2, 3, 4, 5, 6-Pentafluorobenzoylchloride (PFBC). Both Negative CI and Positive CI modes of analysis were compared to the more widely accepted EI modes of mass spectrometric analysis.

Confounding contaminants in mass spectrometric reaction monitoring

2019 ◽  
Author(s):  
Gilian T. Thomas ◽  
Landon MacGillivray ◽  
Natalie L. Dean ◽  
Rhonda L. Stoddard ◽  
Lars Yunker ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Reaction Monitoring ◽  
Schlenk Flask ◽  
Dynamic Analyses ◽  
Rubber Septa ◽  
Negative Ion Mode ◽  
Mode A

<p>Reactions carried out in the presence of rubber septa run the risk of additives being leached out by the solvent. Normally, such species are present at low enough levels that they do not interfere with the reaction significantly. However, when studying reactions using sensitive methods such as mass spectrometry, the appearance of even trace amounts of material can confuse dynamic analyses of reactions. A wide variety of additives are present in rubber along with the polymer: antioxidants, dyes, detergent, and vulcanization agents, and these are all especially problematic in negative ion mode. A redesigned Schlenk flask for pressurized sample infusion (PSI) is presented as a means of practically eliminating the presence of contaminants during reaction analyses.</p>

Author response for "Isomeric effect on the MS dissociation of aglycones of saikosaponins in the negative ion mode"

2020 ◽  
Author(s):  
Guoqiang Liu ◽  
Zunjian Zhang ◽  
Xinji Yang ◽  
Shuyu Zhan ◽  
Xiaoqing Lv ◽  
...  
Keyword(s):  
Negative Ion ◽  
Author Response ◽  
Isomeric Effect ◽  
Negative Ion Mode
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