Evaluation of Coupling Reversed Phase, Aqueous Normal Phase, and Hydrophilic Interaction Liquid Chromatography with Orbitrap Mass Spectrometry for Metabolomic Studies of Human Urine
In this study, we assessed three liquid chromatographic platforms: reversed phase (RP), aqueous normal phase (ANP), and hydrophilic interaction (HILIC) for the analysis of polar metabolite standard mixtures and for their coverage of urinary metabolites. The two zwitterionic HILIC columns showed high-quality chromatographic performance for metabolite standards, improved separation for isomers, and the greatest coverage of polar metabolites in urine. In contrast, on the reversed phase column, most metabolites eluted very rapidly with little or no separation. Using an Exactive Orbitrap mass spectrometer with a HILIC liquid chromatographic platform, approximately 970 metabolite signals with repeatable peak areas (relative standard deviation (RSD) ≤ 25%) could be putatively identified in human urine, by elemental composition assignment within a 3 ppm mass error. The ability of the methodology for the verification of nonmolecular ions, which arise from adduct formation, and the possibility of distinguishing iso...
Tong Zhang; Darren J. Creek; Michael P. Barrett; Gavin Blackburn; David G. Watson
We recently generalized the formerly alignment-dependent multivariate image analysis applied to quantitative structure–activity relationships (MIA-QSAR) method through the application of the discrete Fourier transform (DFT), allowing for its application to noncongruent and structurally dive ... more
Poly-ADP-ribosylation (PARylation) is a protein posttranslational modification (PTM) that is critically involved in many biological processes that are linked to cell stress responses. It is catalyzed by a class of enzymes known as poly-ADP-ribose polymerases (PARPs). In particular, PARP1 is ... more
This review focuses on the type A cytochrome c oxidases (CcO), which are found in all mitochondria and also in several aerobic bacteria. CcO catalyzes the respiratory reduction of dioxygen (O2) to water by an intriguing mechanism, the details of which are fairly well understood today as a r ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more