scholarly journals Relative quantitative analysis of human plasma O‑sulfotyrosine using HPLC‑MS/MS in linear negative ion mode

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Daopeng Dai ◽  
Zhanwei Ruan ◽  
Hui Han ◽  
Jinzhou Zhu ◽  
Ruiyan Zhang
Keyword(s):  
Quantitative Analysis ◽  
Human Plasma ◽  
Negative Ion ◽  
Negative Ion Mode

scholarly journals Liquid Chromatography/Tandem Mass Spectrometry for the Simultaneous Determination of Ursodiol and its Major Metabolites, Tauroursodeoxycholic Acid and Glycoursodeoxycholic Acid in Human Plasma

2012 ◽  
Vol 9 (3) ◽  
pp. 1605-1612
Author(s):  
M. Ganesan ◽  
S. Nanjundan ◽  
S. Viswanathan ◽  
G. Uma
Keyword(s):  
Human Plasma ◽  
Solid Phase ◽  
Internal Standard ◽  
Bioequivalence Study ◽  
Negative Ion ◽  
Limit Of Quantification ◽  
Tauroursodeoxycholic Acid ◽  
Liquid Chromatography Tandem Mass ◽  
Glycoursodeoxycholic Acid ◽  
Negative Ion Mode

A rapid and sensitive method is described for the quantification of ursodiol and its major metabolites glycoursodeoxycholic acid (GUDCA) and tauroursodeoxycholic acid (TUDCA) in human plasma using single internal standard (Ursodeoxycholic Acid d4). Solid phase extraction was performed and chromatographic separation of 5µL injected sample was achieved using Waters Xterra, 5µm column with a mobile phase comprised of methanol and 5 mM ammonium formate with 0.1 % acetic acid ( 70 : 30, v/v ). The mass spectrometer was used in negative ion mode and multiple reactions monitoring using electro spray ionization mode as an interface. The method was fully validated and the calibration curves were linear over the concentration range of 25.9 to 15300.1 ng/mL for ursodiol, 2.7 to 1587.5ng/mLfor tauroursodeoxycholicacid and 25.4 to 15040.9 ng/mL for glycoursodeoxycholic acid. The method was sensitive and specific, with the lower limit of quantification of 25.9, 2.7 and 25.4 ng/ml for ursodiol, tauroursodeoxycholic acid and glycoursodeoxycholic acid respectively. The present method includes a simple and rapid sample preparation with shorter analysis run time and less flow rate compared to previously reported methods. The method was applied successfully for a bioequivalence study in healthy subjects.

scholarly journals Quantification of Niacin and Its Metabolite Nicotinuric Acid in Human Plasma by LC-MS/MS: Application to a Clinical Trial of a Fixed Dose Combination Tablet of Niacin Extended-Release/Simvastatin (500 mg/10 mg) in Healthy Chinese Volunteers

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Pingping Zhang ◽  
Yantong Sun ◽  
Guobing Shi ◽  
Yin Sui ◽  
Qiuying Li ◽  
...  
Keyword(s):  
Human Plasma ◽  
Extended Release ◽  
Internal Standard ◽  
Negative Ion ◽  
Fixed Dose ◽  
Ionization Source ◽  
Combination Tablet ◽  
Dose Combination ◽  
Relative Errors ◽  
Negative Ion Mode

Our paper aimed to develop rapid, sensitive, and specific LC-MS/MS method for the quantification of niacin (NA) and its metabolite nicotinuric acid (NUA) in human plasma. Following protein precipitation with acetonitrile, the NA, NUA, and internal standard (5-fluorouracil) were separated on a Zorbax 300SB-C8column (250 mm × 4.6 mm, 5 μm) with a mobile phase consisting of methanol-2 mM ammonium acetate (3 : 97, v/v) at a flow rate of 1 mL/min (split 1 : 1). A tandem mass spectrometer equipped with electrospray ionization source was used as the detector and operated in negative ion mode. The linear concentration ranges of the calibration curves were 5–800 ng/mL for NA and NUA. The intra-assay RSD for quality control (QC) samples were from 5.0% to 8.7% for NA, and 5.5% to 7.6% for NUA. The interassay RSD for QC samples were from 2.8% to 9.4% for NA, and 3.7% to 5.8% for NUA. The relative errors for QC samples were from −2.2% to 2.3% for NA, and −0.6% to 3.2% for NUA. The method was successfully applied to the investigation of the pharmacokinetic profiles of NA, NUA in human after single dose administration of Niacin extended-release/Simvastatin tablet (500 mg/10 mg).

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>

scholarly journals Dopant-Enriched Nitrogen Gas for Enhanced Electrospray Ionization of Released Glycans in Negative Ion Mode

2021 ◽  
Author(s):  
Katarina Madunić ◽  
Sander Wagt ◽  
Tao Zhang ◽  
Manfred Wuhrer ◽  
Guinevere S.M. Lageveen-Kammeijer
Keyword(s):  
Electrospray Ionization ◽  
Negative Ion ◽  
Nitrogen Gas ◽  
Negative Ion Mode
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