MoO-19
SPECTROMETRY / MASS SPECTROMETRY USING SELECTED REACTION MONITORING
Bruce Tattam*, Victor Awad*, Douglas Moore*, Latifu Sanni# & Nicholas Hunt#
*Department of Pharmacy, University of Sydney 2006
#Department of Pathology, University of Sydney 2006
Quinolinic acid (Quin) is a neurotoxic metabolite produced in the L-tryptophan pathway, the reasons as to its production are not clearly understood but it is evident that elevated levels of Quin in the brain have been implicated in the neuronal damage seen in the infected brains of patients with a variety of diseases, the focus of this research is on cerebral malaria (CM). There is believed to be a link between the dementia seen in CM patients and that seen in AIDS patients. There are over 400 million cases of malaria in the world, and approx 2 million deaths can be attributed to cerebral complications.
This assay developed is an improvement over past assays developed for the determination of QUIN in brain. Reported assays involve the use of complex ion chromatographic extraction procedures. The use of mass spectrometry/mass spectrometry (ms/ms) acts as a chromatographic step by filtering ions formed and looking for fingerprints of the compound created by a reaction within the mass spectrometer.The assay uses a simple homogenisation step, followed by lyophilization of the samples and utilising a base catalysed anhydrous pentafluorobenzylation. The Mass Spectroscopic assay developed uses negative ion chemical ionisation in selected ion reaction monitoring mode. A detection limit of 6 femtograms was achieved with this
assay, normal assay range of 10 to 500 picograms. Some data and assay validation data will be presented in the paper.