电喷雾四级杆飞行时间 Qtof理论.pptVIP

Atmospheric Pressure Ionization- Electrospray Ionization (API-ESI) Ion generation for MS analysis Nebulization Desolvation Coulomb explosions Desorption Generation of Ions-Desolvation Generation of Ions-Ion Evaporation Quadrupole Mass Analyzer Collision Cell multiple charged ion Tune Parameters Ion Optics Helpful Tips 质谱基本术语： 分辨率 Mass Resolution 同位素分布模式 Isotope Patterns 单同位素质量 Monoisotopic Mass ………………. It is a measure of a mass spectrometer’s ability to distinguish two compounds of nearly equal mass. 600 800 1000 1200 1400 1600 1800 2000 2200 2400 m/z 100 200 300 400 500 600 700 800 900 1000 1100 a.i. 1618 1623 1628 m/z -301- -273- “easy” “not so easy” Resolution What is meant by ‘Resolution’? The narrower the FWHM, the higher the resolution. With the same FWHM, higher masses will have higher resolution than lower masses. Resolution = (m/z) / FWHM FWHM Full Width at Half Maximum m/z How do we measure mass resolution? Isotopic Distribution Patterns 13 12 100 90 80 70 60 50 40 30 20 10 0 C1 122 121 120 100 90 80 70 60 50 40 30 20 10 0 C10 1,206 1,204 1,202 1,200 100 90 80 70 60 50 40 30 20 10 0 C100 12,030 12,020 12,010 12,000 100 90 80 70 60 50 40 30 20 10 0 C1000 Isotopes are atoms with the same number of protons in the nuclei, but with different numbers of neutrons. Only 21 elements have only one stable isotope. All other elements are mixtures of at least 2 stable isotopes, and the proportions of these isotopes can vary greatly depending on the element. Carbon has 2 stable isotopes, C-12 and C-13, with natural abundance of 98.892% and 1.108% respectively. As the number of carbons increase in a molecule, the isotopic distribution pattern will reflect the mass contribution of the isotopes with their extra neutrons. pQLYENKPRRPYIL MW 1672.9 Res. 1,000 1,682 1,680 1,678 1,676 1,674 1,672 100 90 80 70 60 50 40 30 20 10 1673.9 Average Mass 40 1,682 1,680 1,678 1,676 1,674 1,672 100 90 80 70 60 50 30 20 10 0 Res. 10,000 [M+H]+ [M+H+1]+ [