Basic mass spectrometry pot

Basic mass spectrometry Approach of Proteomics Sample pre-treatment Separation of proteins Digestion of separated proteins Mass spectrometry analysis Identification via Database search [...]... C19H7N+ 249.0580 249.1479 C13H19N3O2+ The fundamentals of accurate mass carbon hydrogen oxygen nitrogen has has has has a a a a mass mass mass mass of of of of 12.0000 1.0078 15.9949 14.0031 It is possible to have combinations of atoms which have the same nominal (or integer) mass but different accurate mass If such compounds can be mass measured with sufficient accuracy it is possible to determine... Desorption Electrospray Ionization Mass Spectrometry Terminology Mass Nominal Mass The mass of an ion with a given empirical formula calculated using the integer mass numbers of the most abundant isotope of each element Ex : M=249 C20H9+ or C19H7N+ or C13H19N3O2+ Exact Mass The mass of an ion with a given empirical formula calculated using the exact mass of the most abundant isotope of each element 249.0070... of ions in pusher Vpusher Time = 0 Resolution example Mass range Mass Range is usually defined by the lower and upper m/z value observable by a mass analyzer If your compound mass does not fall in the mass range of the mass analyzer, it will not be detected ! More than one charge (multiply charge ion) allows the ion to be measured at a lower m/z Mass range: Multiply charged molecules 5 µmol Cytochrome... [M+18H] 700 750 800 850 m/z 900 950 1,000 Mass accuracy Ability of a mass analyzer to assign the mass of an ion close to its true value (exact mass) ∆m accuracy = mreal - mmeasured ppm = 106 * ∆m accuracy / mmeasured ∆m accuracy High mass accuracy (exact mass measurement) is usually associated to high resolution analyzers Goals : - Unknown compound determination Exact mass helps to define its atomic/elemental... acquire a mass spectrum, (mass units/sec or amu/sec) It is an essential acquisition parameter for MS Will affect the amount of information (qualitative and quantitative) that can reasonably be attained with a given mass analyzer Mass Analyzers Mass analyzer characteristics Operate at very low pressure (10-5 to 10-7 torr) {atmosphere = 760 torr} Measure gas-phase ions Determine the mass of as mass- to-charge... torr} Measure gas-phase ions Determine the mass of as mass- to-charge ratio (m/z) Types of mass analyzers Time-of-Flight Mass Spectrometer Triple Quadrupole Mass Spectrometer Quadrupole Time-of-Flight Mass Spectrometer Ion-Trap Mass Spectrometer Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Time-of-Flight Mass Spectrometer TOF analyzer measures the m/z ratios of ions based on the time it takes... with a mass analyzer The mass analyzer is equipped with an atmospheric interface connected via a flexible extanded ion transfer line Show the capability of analyzing a range of compounds from nonpolar small molecules to polar peptides and proteins The potential exists for direct monitoring of proteins on the surface of cells in culture from tissue sections Desorption Electrospray Ionization Mass Spectrometry. .. Resolution Resolution, equally called Resolving Power, of a mass spectrometer is a measure of its ability to separate adjacent ions At higher resolution, small mass differences may be detected C20H9+ C19H7N+ C13H19N3O2+ C20H9+ C19H7N+ 3 different compounds Same nominal mass Low resolution C13H19N3O2+ 3 different compounds 3 different exact masses High resolution 249 249.0070 249.0580 249.1479 Determining... analysis Exact mass proves the presence of a particular ion in a mixture Mass accuracy vs resolution Sensitivity Term used to describe the ability of the MS to respond to a given amount of analyte at a given mass to charge ratio The sensitivity of your LC/MS system is directly related to the efficiencies of all the processes of the entire system : LC separation and flow Interface Ionization Mass transmission... solid mixture MALDI source region at a relatively high pressure, mass analyzer region at a low pressure MALDI can produce both positive and negative ions Positive ions are formed by the acceptance of a proton as the analyte leaves the matrix In MALDI, peptide and large biomolecular ions are singly charged MALDI is typically interfaced with mass analyzers with large m/z ranges such as TOF spectrometers . Basic mass spectrometry Approach of Proteomics Sample pre-treatment Separation of proteins Digestion of separated proteins Mass spectrometry analysis Identification. proteins.  The potential exists for direct monitoring of proteins on the surface of cells in culture from tissue sections. Desorption Electrospray Ionization Mass Spectrometry Terminology Mass Nominal Mass The. 249.1479 The fundamentals of accurate mass  carbon has a mass of 12.0000  hydrogen has a mass of 1.0078  oxygen has a mass of 15.9949  nitrogen has a mass of 14.0031  It is possible to have