Matrix laser desorption ionization (MALDI) time-of-flight mass spectrometry (TOFMS) studies of arylamine DNA adducts and cross-linked hemoglobin

Mass spectrometry (MS) is an analytical tool to measure the mass-to-charge ratio (m/z) of ions. Matrix assisted laser desorption ionization (MALDI) is an ion formation technique to provide sample ions for the measurements. One of most important characteristics of MALDI is the ability to produce intact ions from very large molecules without destroying their structures. Therefore, it has been widely used as the ion source for MS analyses of large biological molecules.{09}MALDI is typically connected with a time of flight (TOF) mass analyzer. The spectrum is acquired by recording the flight time of the ion in a drift tube, which is dependant on the m/z value of the ion.{09}The product ion analysis using TOFMS is called post source decay (PSD), and it provides more detailed structural information.; MALDI coupled with TOFMS and PSD was used in the structural characterization of arylamine DNA adducts. The limit of detection (LOD) for the adducts were determined at fetomole level.{09}This sensibility may allow us to analyze those adduct from human resource, such as placenta.{09}We examined the product ion formation characteristics and Identified structure-specific fragmentation pathways for some synthetic arylamine deoxyguanosine adducts, which will be used to recognize the same arylamine adducts isolated from in vivo sources so as to provide the evidence of their existence in vivo. The precursor ion activation by direct absorption of laser light was also investigated.; MALDI-TOFMS was used to identify cross-linking site in cross-linked human hemoglobin by a series of diaspirin reagents that may be used as a blood substitute. The cross-linked hemoglobin was prepared under both oxy and deoxy conditions. The MS results of CNBr fragments provided the evidence of cross-linking between two β chains, and those of tryptic fragments suggested the cross-linking of β1–β82 and β8–β95.