Investigation of the chemical structure and formation mechanism of polydopamine from self-assembly of dopamine by liquid chromatography/mass spectrometry coupled with isotope-labelling techniques

2019 ◽  
Vol 33 (5) ◽  
pp. 429-436 ◽  
Author(s):  
Wan Chan
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Formation Mechanism ◽  
Self Assembly ◽  
Chemical Structure ◽  
Liquid Chromatography Mass Spectrometry ◽  
Isotope Labelling ◽  
Chromatography Mass Spectrometry

scholarly journals Simultaneous Measurement of Urinary Trimethylamine (TMA) and Trimethylamine N-Oxide (TMAO) by Liquid Chromatography–Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1862
Author(s):  
Xun Jia ◽  
Lucas J. Osborn ◽  
Zeneng Wang
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Slow Rate ◽  
Chemical Structure ◽  
Prolonged Storage ◽  
Alkaline Ph ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Excellent Candidate ◽  
Inflammatory State

Trimethylamine (TMA) is a gut microbial metabolite—rendered by the enzymatic cleavage of nutrients containing a TMA moiety in their chemical structure. TMA can be oxidized as trimethylamine N-oxide (TMAO) catalyzed by hepatic flavin monooxygenases. Circulating TMAO has been demonstrated to portend a pro-inflammatory state, contributing to chronic diseases such as cardiovascular disease and chronic kidney disease. Consequently, TMAO serves as an excellent candidate biomarker for a variety of chronic inflammatory disorders. The highly positive correlation between plasma TMAO and urine TMAO suggests that urine TMAO has the potential to serve as a less invasive biomarker for chronic disease compared to plasma TMAO. In this study, we validated a method to simultaneously measure urine TMA and TMAO concentrations by liquid chromatography–mass spectrometry (LC/MS). Urine TMA and TMAO can be extracted by hexane/butanol under alkaline pH and transferred to the aqueous phase following acidification for LC/MS quantitation. Importantly, during sample processing, none of the nutrients with a chemical structure containing a TMA moiety were spontaneously cleaved to yield TMA. Moreover, we demonstrated that the acidification of urine prevents an increase of TMA after prolonged storage as was observed in non-acidified urine. Finally, here we demonstrated that TMAO can spontaneously degrade to TMA at a very slow rate.

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