Mass Spec Tools

Avanti offers two types of Chemical Mass Spectrometry tools. The first class is DMABA NHS ester reagents. Deuterium enriched 4-(dimethylamino) benzoic acid (DMABA) N-hydroxysuccinimide (NHS) ester reagents (d0, d4, d6, d10) derivatize the primary amine group of lipids, such as PE lipid species1. The subclasses of PE lipids (diacyl, ether, and plasmalogen) do not produce similar fragmentation patterns in positive ion mode or negative ion mode electrospray tandem mass spectrometry, which makes detection of PE subclasses within biological samples or complex mixtures difficult1. Specifically, tandem mass spectrometry most commonly detects PE subclasses by monitoring a neutral loss of 141 (NL141) amu, which is fragmentation associated with the loss of the PE headgroup1. However, only diacyl and ether PE species undergo efficient fragmentation of the polar headgroup whereas plasmalogen PE species produce only a very minor ion resulting from the NL141 amu1. The DMABA NHS ester reagents were developed by Dr. Robert Murphy’s laboratory at the University of Colorado (Denver, CO) in order to create PE derivatives where all subclasses and potentially oxidized products could be universally detected using a common precursor ion in the positive ion mode.1,2

The second class is Girard Reagent. The Girard reagents are a family of quaternary ammonium hydrazides usually containing pyridine or trimethylamine (TMA) moieties. These are used to derivatize oxysterols. This converts the charged neutral oxysterol to a strongly positively charged hydrazone which provides enhanced solubility and ionization capacity. When subjected to MS/MS, these hydrazones undergo loss of pyridine or TMA. The net positive charge is then transferred to the sterol backbone, and upon collision-induced dissociation (CID), several structure-specific fragments are produced.3

  • Zemski Berry, K.A., W.W. Turner, M.S. VanNieuwenhze, and R.C. Murphy. (2009). Stable isotope-labeled 4-(dimethylamino) benzoic acid derivatives of glycerophosphoethanolamine lipids. Anal Chem 81:6633-40.
  • Zemski Berry, K.A., W.W. Turner, M.S. VanNieuwenhze, and R.C. Murphy. (2010). Characterization of oxidized phosphatidylethanolamine derived from RAW 264.7 cells using 4-(dimethylamino)benzoic acid derivatives. Eur J Mass Spectrom (Chichester, Eng) 16:463-70.
  • Lavrynenko, O., Nedielkov, R., Moller, H. (2013). Girard derivatization for LC-MS?MS profiling of endogenous ecdysteroids in Drosophila. J. Lip. Res. 54:2265-2272