Glutathione Trapping: Investigating Methods of Detection of Glutathione Adducts

Xenobiotics can show idiosyncratic toxicity due to the formation of reactive metabolites. Glutathione (GSH) can be used as a marker for such reactive species by covalently binding to electrophilic sites using the thiol sulfur. Once the reactive metabolites are trapped by GSH they require separation by ultra high pressure liquid chromatography (UPLC) and identification using mass spectrometry.  There are several mass spectrometry methods that can be utilised to detect the GSH adducts, including negative ion MSE acquisition and subsequent extraction of m/z 272.0883 and positive ion neutral loss of 129 Da.  Here we present complementary methods for data aquisition and interrogation in order to maximise metabolic coverage of GSH-metabolite conjugates.  This was investigated through the evaluation of mass spectrometric methods; including extraction of m/z 272.0883 from negative ion MS^E, positive ion neutral loss of 129 Da and negative ion precursor of m/z 272, supplemented by a combination of manual and software assisted interrogation.