Guanidinated protein internal standard for immunoaffinity‐liquid chromatography/tandem mass spectrometry quantitation of protein therapeutics

Abstract

The proposed strategy allows LC/MS/MS to play an ever-increasing role in bioanalytical support for protein therapeutics development because of its capability of completely tracking all variations from the beginning to the end of sample analysis, easier preparation compared to isotope-labeled protein-IS, and greater flexibility for changing to alternate analyte surrogate peptides.

Applications of Mass Spectrometry for Clinical Diagnostics: The Influence of Turnaround Time

“…DART is particularly versatile because it embodies three distinct ionization mechanisms that enable the analysis of various kinds of small molecules, including polar and nonpolar species. 14,129,131 The first and predominant mechanism involves proton transfer reactions that produce (M + H) + ions after analytes interact with protonated water clusters, H + (H 2 O) n , formed from a cascade of events in the plasma. The second mechanism entails Penning ionization in which the excited state metastable helium gas accepts an electron into its ground-state atomic orbital from the analyte (M), resulting in concomitant formation of its molecular ion (M •+ ), and the release of an electron that was initially present in the excitedstate orbital of helium.…”

An optimized guanidination method for large‐scale proteomic studies

“…NH 3 .H 2 O, NaOH or Na 2 CO 3 [1][2][3][4]26]. Although several obvious advantages had been claimed using NH 3 .H 2 O as the reaction buffer, including the easy removal of NH 3 .H 2 O by evaporation and avoiding the introduction of metal ion which often interferes MS detection [27], the sodium buffers are also adapted in some studies [8,[28][29][30].…”

“…It is believed that the reaction should be carried out at pH > 10 to ensure the deprotonation of ε–amine; and in practice the high pH is often achieved by the addition of NH 3 .H 2 O, NaOH or Na 2 CO 3 . Although several obvious advantages had been claimed using NH 3 .H 2 O as the reaction buffer, including the easy removal of NH 3 .H 2 O by evaporation and avoiding the introduction of metal ion which often interferes MS detection , the sodium buffers are also adapted in some studies .…”

Direct Analysis of Carbonyl Compounds by Mass Spectrometry with Double-Region Atmospheric Pressure Chemical Ionization

“…APCI, using corona discharge at atmospheric pressure, represents a soft-ionization method where molecular ions play the dominant role in mass spectrum. APCI-MS is therefore conveniently applied in gas sample analysis and has been used in a number of areas including exhalation in medical application, 28 food flavor classification, 29−31 VOC and biogenic VOC detection, 32−35 and chemical warfare agent monitoring. 36−39 Meanwhile, APCI has been modified to improve ionization efficiency and simplify analytical procedures.…”