ESI-MS/MS analysis of protonated N -methyl amino acids and their immonium ions

2019 ◽  
Vol 54 (9) ◽  
pp. 761-771
Author(s):  
Pavankumar Pallerla ◽  
Sudarshana Reddy Bhumireddy ◽  
Sai Sachin Lingampally ◽  
Nagarjuna Chary Ragi ◽  
Prabhakar Sripadi
Keyword(s):  
Amino Acids ◽  
Esi Ms ◽  
Ms Analysis ◽  
Immonium Ions

Dependence of matrix effect on ionization polarity during LC–ESI–MS analysis of derivatized amino acids in some natural samples

2017 ◽  
Vol 23 (5) ◽  
pp. 245-253 ◽  
Author(s):  
Maarja-Liisa Oldekop ◽  
Riin Rebane ◽  
Koit Herodes
Keyword(s):  
Amino Acids ◽  
Matrix Effect ◽  
Negative Ion ◽  
Herbal Extracts ◽  
Esi Ms ◽  
Ms Analysis ◽  
The Matrix ◽  
Negative Ion Mode ◽  
Positive Ion ◽  
Sample Dilution

Matrix effect, the influence of co-eluting components on the ionization efficiency of the analyte, affects the trueness and precision of the LC–ESI–MS analysis. Derivatization can reduce or eliminate matrix effect, for example, diethyl ethoxymethylenemalonate (DEEMM) derivatives have shown less matrix effect compared to other derivatives. Moreover, the use of negative ion mode can further reduce matrix effect. In order to investigate the combination of derivatization and different ionization modes, an LC–ESI–MS/MS method using alternating positive/negative ion mode was developed and validated. The analyses in positive and negative ion modes had comparable limit of quantitation values. The influence of ESI polarity on matrix effect was investigated during the analysis of 22 DEEMM-derivatized amino acids in herbal extracts and honeys. Sample dilution approach was used for the evaluation of the presence of matrix effect. Altogether, 4 honeys and 11 herbal extracts were analyzed, and the concentrations of 22 amino acids in the samples are presented. In the positive ion mode, matrix effect was observed for several amino acid derivatives and the matrix effect was stronger in honey samples compared to the herbal extracts. The negative ion mode was free from matrix effect, with only few exceptions in honeys (average relative standard deviation over all analytes and matrices was 8%; SD = 7%). The matrix effect was eliminated in the positive ion mode by sample dilution and agreement between concentrations from the two ion modes was achieved for most amino acids. In conclusion, it was shown that the combination of derivatization and negative ion mode can be a powerful tool for minimizing matrix effect in more complicated applications.

LC-ESI-MS/MS analysis of Quassia amara leaves tea. Is antiplasmodial activity of the tea is due to quassinoids?

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
N Fabre ◽  
E Deharo ◽  
HL Le ◽  
C Girardi ◽  
A Valentin ◽  
...  
Keyword(s):  
Antiplasmodial Activity ◽  
Esi Ms ◽  
Ms Analysis ◽  
Quassia Amara

LC-DAD-ESI-MS/MS analysis, cytotoxic and antiproliferative effect of chlorogenic acid derivates rich extract from Nerium oleander L. pink flowers

2021 ◽  
Author(s):  
Siham Ayouaz ◽  
Sheila Cristina Oliveira-Alves ◽  
Ana Teresa Serra ◽  
Khalef LEFSIH ◽  
Madani Samah ◽  
...  
Keyword(s):  
Medicinal Plant ◽  
Chlorogenic Acid ◽  
Antiproliferative Effect ◽  
Nerium Oleander ◽  
Phenolic Composition ◽  
Esi Ms ◽  
Ms Analysis

Nerium oleander L, is a medicinal plant widely used for pharmaceutical purposes. In this work the pink flowers of this plant were characterized in terms of phenolic composition by LC-DAD-ESI-MS/MS...

NMR, HPLC-ESI-MS, and MALDI-TOF MS Analysis of Condensed Tannins from Delonix regia (Bojer ex Hook.) Raf. and Their Bioactivities

2012 ◽  
Vol 60 (19) ◽  
pp. 5013-5022 ◽  
Author(s):  
Wei-Ming Chai ◽  
Yan Shi ◽  
Hui-Ling Feng ◽  
Ling Qiu ◽  
Hai-Chao Zhou ◽  
...  
Keyword(s):  
Condensed Tannins ◽  
Maldi Tof Ms ◽  
Esi Ms ◽  
Delonix Regia ◽  
Maldi Tof ◽  
Ms Analysis ◽  
Tof Ms

Comparison of silylation and esterification/acylation procedures in GC-MS analysis of amino acids

2003 ◽  
Vol 26 (17) ◽  
pp. 1474-1478 ◽  
Author(s):  
Tim G. Sobolevsky ◽  
Alexander I. Revelsky ◽  
Barbara Miller ◽  
Vincent Oriedo ◽  
Elena S. Chernetsova ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ms Analysis

UPLC-ESI-MS/MS analysis of Sudan dyes and Para Red in food

2010 ◽  
Vol 27 (9) ◽  
pp. 1215-1220 ◽  
Author(s):  
C. Li ◽  
Y.L. Wu ◽  
J.Z. Shen
Keyword(s):  
Sudan Dyes ◽  
Esi Ms ◽  
Ms Analysis
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