Journal ArticleDOI
Mitigation of signal suppression caused by the use of trifluoroacetic acid in liquid chromatography mobile phases during liquid chromatography/mass spectrometry analysis via post-column addition of ammonium hydroxide
TLDR
A method has been developed to reduce the mass spectrometric ion signal suppression associated with the use of TFA as an additive in LC mobile phases through post-column infusion of diluted NH(4)OH solution to LC eluents.Abstract:
A method has been developed to reduce the mass spectrometric ion signal suppression associated with the use of TFA as an additive in LC mobile phases. Through post-column infusion of diluted NH4OH solution to LC eluents, the ammonium ion introduced causes the neutral analyte-TFA ion pair to dissociate which consequently releases the protonated analyte as free ions into the gas phase (through regular electrospray ionization mechanisms). An ion signal improvement from 1.2 to 20 times for a variety of compounds had been achieved through the application of this method. The molar ratios of NH4OH:TFA which result in a reduction of signal suppression were determined to be between 0.5:1 and 50:1. In addition, it was shown that this NH4OH infusion method could reduce the level of doubly-charged species and the product ions formed via in-source collision. The use of diluted NH4OH solution is favorable since it is compatible with mass spectrometry analysis, and it is applicable in both positive and negative-ion generation mode. Copyright © 2012 John Wiley & Sons, Ltd.read more
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Critical practical aspects in the application of liquid chromatography–mass spectrometric studies for the characterization of impurities and degradation products
Mallikarjun Narayanam,Tarun Handa,Parul Sharma,Shalu Jhajra,Praveen Kumar Muthe,Pavan Kumar Dappili,Ravi P. Shah,Saranjit Singh +7 more
TL;DR: Liquid chromatography-mass spectrometry (LC-MS) is considered today as a mainstay tool for the structure characterization of minor components like impurities and degradation products in drug substances and products.
Journal ArticleDOI
Improving detection sensitivity of amino acids in thyroid tissues by using phthalic acid as a mobile phase additive in hydrophilic interaction chromatography-electrospray ionization-tandem mass spectrometry.
TL;DR: The enhanced detection and separation of AAs were obtained by merely adding phthalic acid to the mobile phase without changing other conditions, demonstrating a significant increase of most AAs in thyroid carcinoma tissues (p<0.05).
Journal ArticleDOI
Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns?
TL;DR: It is concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column.
Journal ArticleDOI
Utility of Ion Mobility Mass Spectrometry for Drug-to-Antibody Ratio Measurements in Antibody-Drug Conjugates.
Richard Y.-C. Huang,Ekaterina G. Deyanova,David Passmore,Vangipuram S. Rangan,Shrikant Deshpande,Adrienne A. Tymiak,Guodong Chen +6 more
TL;DR: In this study, the practical utility of ion mobility mass spectrometry (IM-MS) in a routine LC/MS workflow for DAR measurements is illustrated, providing significant improvement of signal-to-noise ratios of ADC intact mass spectra for accurate DAR measurements.
Journal ArticleDOI
A novel liquid chromatography/mass spectrometry method for determination of neurotransmitters in brain tissue: Application to human tauopathies.
Andrea Forgacsova,Jaroslav Galba,Ralph M. Garruto,Petra Majerova,Stanislav Katina,Andrej Kovac +5 more
TL;DR: The present study is the first to demonstrate significant alterations of brain neurotransmitters caused by pathological processes in the brain tissues of patient with three different tauopathies.
References
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Journal ArticleDOI
Ion Suppression in Mass Spectrometry
TL;DR: Options for minimizing or correcting ion suppression are presented, which include enhanced specimen cleanup, chromatographic changes, reagent modifications, and effective internal standardization.
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Surface Tension of Alcohol Water + Water from 20 to 50 .degree.C
TL;DR: In this paper, the surface tension of aqueous solutions of methanol, ethanol, 1-propanol, and 2propanols was measured over the entire concentration range at temperatures of 20-50 C. The experimental values were correlated with temperature and with mole fraction.
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Mobile and localized protons: a framework for understanding peptide dissociation
TL;DR: In this paper, surface-induced dissociation, along with gas-phase collision-induced disociation performed under a variety of conditions, has been used to refine the general'mobile proton' model and to determine how and why enhanced cleavages occur at aspartic acid residues and protonated histidine residues.
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A study of ion suppression effects in electrospray ionization from mobile phase additives and solid-phase extracts
TL;DR: A simple setup for quantification of ion suppression/enhancement of solid-phase liquid chromatography/tandem mass spectrometry (SPE/LC/MS/MS) systems was described and it was demonstrated that a clean up of plasma extracts based on ion exchange leads to minimal ion suppressed for the compounds that were investigated.
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Effect of eluent on the ionization process in liquid chromatography-mass spectrometry.
TL;DR: The review presents an overview of studies concerning the effect of eluent composition on the ionization efficiency of ESI, APCI and APPI in LC-MS, and solvent characteristics are discussed in the light of ionization theories.