1.Tutorial on Mass Spectrometry, Isotopes Identification and Option A HL.Prepared by Lawrence Kok http://lawrencekok.blogspot.com

2. Mass Spectrometer Uses mass spectrometer Relative atomic mass of an elementRelative Molecular mass of a moleculeCO2 3. Mass Spectrometer Uses mass spectrometer Relative atomic mass of an elementRelative Molecular mass of a moleculeCO2Presence of isotopes and its abundance 4. Mass Spectrometer Uses mass spectrometer Relative atomic mass of an elementRelative Molecular mass of a moleculePresence of isotopes and its abundanceCO2Organic structure determination Distinguish between structural isomersCH3CH2CH2OHStructure of organic compoundOH | CH3CHCH3CH3 | CH3C-CH3 | CH3structural formula 5. Mass Spectrometer Parts of Mass Spectrometer 1Vaporization2IonizationSample injection3Accelerator4Deflector5Detector 6. Mass Spectrometer Parts of Mass Spectrometer 1Vaporization2IonizationSample injection1Vaporization Chamber Sample heat to vapour state2Ionization Chamber Molecule bombard with electrons form positive ionsSample X bombarded by electron Form positive M+ ion Accelerated (Electric Field) Deflected (Magnetic Field) and Detected X + e- X+ + 2e-3Accelerator4Deflector5Detector 7. Mass Spectrometer Parts of Mass Spectrometer 1Vaporization23IonizationAccelerator45DeflectorDetectorSample injection5Detector 1 Convert abundance of M+ ions to electrical current. M+ ions neutralize by electrons (more e needed - higher current higher intensity of peak) Intensity of peak show -relative abundance of ionsVaporization Chamber Sample heat to vapour state2Ionization Chamber Molecule bombard with electrons form positive ionsSample X bombarded by electron Form positive M+ ion Accelerated (Electric Field) Deflected (Magnetic Field) and Detected X + e- X+ + 2e-3Accelerator Chamber M+ions accelerated by Electric field4Deflector M+ions deflected by magnetic field 8. Mass Spectrometer Parts of Mass Spectrometer 1Vaporization23IonizationAccelerator45DeflectorDetectorSample injection5Detector 1 Convert abundance of M+ ions to electrical current. M+ ions neutralize by electrons (more e needed - higher current higher intensity of peak) Intensity of peak show -relative abundance of ionsVaporization Chamber Sample heat to vapour state2Ionization Chamber Molecule bombard with electrons form positive ions3Accelerator Chamber M+ions accelerated by Electric field4Deflector M+ions deflected by magnetic fieldSample X bombarded by electron Form positive M+ ion Accelerated (Electric Field) Deflected (Magnetic Field) and Detected X + e- X+ + 2e-Click here notes from chemguideDetail notes from chem msu 9. Mass Spectrometer Parts of Mass Spectrometer 1Vaporization2Ionization3AcceleratorClick here for simulation4Deflector5Detector 10. Mass Spectrometer Parts of Mass Spectrometer 11VaporizationVaporization Injection/ vaporization of sample liquid state gaseous2IonizationForm radical cations, M+2Ionization3AcceleratorClick here for simulation4Deflector5Detector 11. Mass Spectrometer Parts of Mass Spectrometer 11Vaporization23IonizationVaporization Injection/ vaporization of sample liquid state gaseousAccelerator4Deflector5DetectorClick here for simulation2IonizationForm radical cations, M+Deflection depend: mass/charge (m/z) ratio: (m/z) ratio HIGH - Deflection LOW 37CI+35CI+35CI2+3Acceleration M+ ions accelerated by Electric field4Deflection M+ ion deflected by magnetic fieldDeflection depend: mass/charge (m/z) ratio: (m/z) ratio LOW- Deflection HIGH 12. Mass Spectrometer Parts of Mass Spectrometer 11Vaporization23IonizationVaporization Injection/ vaporization of sample liquid state gaseousAcceleratorClick here for simulation45Deflector5DetectorDetector Convert abundance of M+ ions to electrical current. M+ ion neutralize by electrons (more e needed - higher current higher intensity of peak) Intensity of peak show -relative abundance of ions2IonizationForm radical cations, M+Deflection depend: mass/charge (m/z) ratio: (m/z) ratio HIGH - Deflection LOW 37CI+35CI+35CI2+3Acceleration M+ ions accelerated by Electric field4Deflection M+ ion deflected by magnetic fieldDeflection depend: mass/charge (m/z) ratio: (m/z) ratio LOW- Deflection HIGH 13. Mass Spectra Online Database Excellent Online Spectra Database. Click here to view1Search methane molecule, CH42Fragmentation pattern CH43Mass Spectrum CH4Mass/charge m/zRelative abundanceMolecular ion peak, M+Isotopic peak M+ + 1Video on mass spectrometerVideo Ionization/fragmentationVideo how MS worksVideo how MS worksVideo Mass spectrometer 14. Relative Atomic MassIsotopes are presentWhy RAM is not a whole number?12 Relative Abundance98.9%13 1.07%RAM = 12.01 Weighted average mass- due to presence of isotopesRelative Isotopic Mass, (Ar) of an element: Relative isotopic mass = Average mass of one atom of element 1/12 x mass of one carbon-12 Relative isotopic mass, carbon = 12.01Relative Isotopic Mass: = (Mass C x % Abundance) + (Mass 13C x % Abundance) = (12 x 98.9/100) + (13 x 1.07/100) = 12.01 12Video on IsotopesVideo on weighted averageVideo on Isotopeshttp://www.tutorvista.com/content/science/science-i/atoms-molecules/atom.phpRAM calculationWeighted average calculation 15. Relative Isotopic Mass Mg - 3 IsotopesRelative Abundance% Abundance Convert relative abundance to % abundance 24 Mg (100/127.2) x 100% - 78.6% Mg (12.8/127.2) x 100% - 10.0% 26 Mg (14.4/127.2) x 100% - 11.3% 25Relative Isotopic Mass: = (Mass 24Mg x % Abundance) + (Mass 25Mg x % Abundance) + (Mass 26Mg x % Abundance) = (24 x 78.6/100) + (25 x 10.0/100) + (26 x 11.3/100) = 24.30 16. Relative Isotopic Mass Mg - 3 IsotopesRelative Abundance% Abundance Convert relative abundance to % abundance 24 Mg (100/127.2) x 100% - 78.6% Mg (12.8/127.2) x 100% - 10.0% 26 Mg (14.4/127.2) x 100% - 11.3% 25Relative Isotopic Mass: = (Mass 24Mg x % Abundance) + (Mass 25Mg x % Abundance) + (Mass 26Mg x % Abundance) = (24 x 78.6/100) + (25 x 10.0/100) + (26 x 11.3/100) = 24.30Pb - 4 IsotopesRelative Abundance% AbundanceConvert relative abundance to % abundance 204Pb (0.2/10) x 100% - 2% (2.4/10) x 100% - 24% 207Pb (2.2/10) x 100% - 22% 208Pb (5.2/10) x 100% - 52% 206PbRelative Isotopic Mass = (Mass 204Pb x % Abundance) + (Mass 206Pb x % Abundance) + (Mass 207Pb x % Abundance) + (Mass 208Pb x % Abundance) = (204 x 2/100) + (206 x 24/100) + (207 x 22/100) + (208 x 52/100) = 207.20 17. Mass spectrometry to determine Relative Isotopic Mass Mg - 3 Isotopes26 Mg- 11.3% - m/z highest deflect LEAST Mg - 10.0% 24 Mg 78.6% - m/z lowest deflect MOST 25Relative Isotopic Mass: = (24Mg x % Ab) + (25Mg x % Ab) + (26Mg x % Ab) = (24 x 78.6/100) + (25 x 10.0/100) + (26 x 11.3/100) = 24.30Deflect MOSTDeflect LEAST 18. Mass spectrometry to determine Relative Isotopic Mass Mg - 3 Isotopes26 Mg- 11.3% - m/z highest deflect LEAST Mg - 10.0% 24 Mg 78.6% - m/z lowest deflect MOST 25Relative Isotopic Mass: = (24Mg x % Ab) + (25Mg x % Ab) + (26Mg x % Ab) = (24 x 78.6/100) + (25 x 10.0/100) + (26 x 11.3/100) = 24.30Deflect MOSTDeflect LEASTPb - 4 Isotopes208Pb 52% - m/z highest deflect LEAST - 22% 206Pb - 24% 204Pb 2% - m/z lowest deflect MOST 207PbRelative Isotopic Mass = (204Pb x % Ab) + (206Pb x % Ab) + (207Pb x % Ab) + (208Pb x % Ab) = (204 x 2/100) + (206 x 24/100) + (207 x 22/100) + (208 x 52/100) = 207.20Deflect MOSTDeflect LEAST 19. Mass spectrometry to determine Relative Isotopic Mass 35CICI - 2 Isotopes37 CI 35 CIRelative Isotopic Mass: = (35CI x % Ab) + (37CI x % Ab) = (35 x 75.5/100) + (37 x 24.5/100) = 35.535CIDeflect MOST37CI 24.5% - m/z highest deflect LEAST 75.5% - m/z lowest deflect MOST37CIDeflect LEAST 20. Mass spectrometry to determine Relative Isotopic Mass 35CICI - 2 Isotopes37 CI 35 CIRelative Isotopic Mass: = (35CI x % Ab) + (37CI x % Ab) = (35 x 75.5/100) + (37 x 24.5/100) = 35.535CIDeflect MOST37CI 24.5% - m/z highest deflect LEAST 75.5% - m/z lowest deflect MOST37CIDeflect LEAST79BrBr - 2 Isotopes81Br81Br 49.3% - m/z highest deflect LEAST 79Br 50.6% - m/z lowest deflect MOSTRelative Isotopic Mass: = (79Br x % Ab) + (81Br x % Ab) = (79 x 50.6/100) + (81 x 49.3/100) = 79.979BrDeflect MOST81BrDeflect LEAST 21. Mass spectrometry to determine Relative Isotopic Mass 1HH - 3 Isotopes3H2H3H trace amt 0.015% - m/z highest deflect LEAST 1H 99.9% - m/z lowest deflect MOST 2HRelative Isotopic Mass: = (1H x % Ab) + (2H x % Ab) = (1 x 99.9/100) + (2 x 0.015/100) = 1.0071HDeflect MOST2HDeflect LEAST 22. Mass spectrometry to determine Relative Isotopic Mass 1HH - 3 Isotopes2H3H3H trace amt 0.015% - m/z highest deflect LEAST 1H 99.9% - m/z lowest deflect MOST 2HRelative Isotopic Mass: = (1H x % Ab) + (2H x % Ab) = (1 x 99.9/100) + (2 x 0.015/100) = 1.0071HDeflect MOST2HDeflect LEAST12CC - 3 Isotopes 14C-13C14Ctrace amt 1.1% - m/z highest deflect LEAST 12C 98.9% - m/z lowest deflect MOST 13CRelative Isotopic Mass: = (12C x % Ab) + (813Cx % Ab) = (12 x 98.9/100) + (13 x 1.1/100) = 12.0112CDeflect MOST13CDeflect LEAST 23. Ionization and Fragmentation Process- CH3CH2CH2CH3Ionization Process - CH3CH2CH2CH3 Bombarded by electron form cation Molecular ion, M+ = 58 (CH3CH2CH2CH3)+ = 58Ionization M+, m/z = 58 CH3CH2CH2CH3 + e CH3CH2CH2CH3+ + 2e H H | | CH3CH2CH2 C:H + e CH3CH2CH2 C+.H + 2e | | m/z = 58 H H 24. Ionization and Fragmentation Process- CH3CH2CH2CH3Ionization Process - CH3CH2CH2CH3 Bombarded by electron form cation Molecular ion, M+ = 58 (CH3CH2CH2CH3)+ = 58Ionization M+, m/z = 58Fragmentation Process CH3CH2CH2CH3 Molecular ion, M+ undergo fragmentation Cation and Radical form Cation - Detected Radical Not detected (No charged)Ionization and Fragmentation of M+ Form - m/z = 58, 43 and 15Ionization and Fragmentation of M+ Form- m/z = 58 and 29CH3CH2CH2CH3 + e CH3CH2CH2CH3+ + 2e H H | | CH3CH2CH2 C:H + e CH3CH2CH2 C+.H + 2e | | m/z = 58 H HIonization forming M+ CH3CH2CH2 : CH3 + e CH3CH2CH2+.CH3 + 2eIonization forming M+ CH3CH2:CH2CH3 + e CH3CH2+CH2CH3 + 2em/z = 58 Fragmentation of M+ producing 43 CH3CH2CH2+CH3 CH3CH2CH2+ + CH3 m/z = 43m/z = 58 Fragmentation of M producing 29 CH3CH2+CH2CH3 CH3CH2+ + .CH2CH3 +m/z = 29 Fragmentation of M+ producing 15 CH3CH2CH2+CH3 CH3CH2CH2 + +CH3 m/z = 15 25. Ionization and Fragmentation Process- CH3CH2CH2CH3Fragmentation Process CH3CH2CH2CH3 Molecular ion, M+ undergo fragmentation Cation and Radical form Cation - Detected Radical Not detected (No charged)Ionization Process - CH3CH2CH2CH3 Bombarded by electron form cation Molecular ion, M+ = 58 (CH3CH2CH2CH3)+ = 58Ionization M+, m/z = 58Ionization and Fragmentation of M+ Form - m/z = 58, 43 and 15Ionization and Fragmentation of M+ Form- m/z = 58 and 29CH3CH2CH2CH3 + e CH3CH2CH2CH3+ + 2e H H | | CH3CH2CH2 C:H + e CH3CH2CH2 C+.H + 2e | | m/z = 58 H HIonization forming M+ CH3CH2CH2 : CH3 + e CH3CH2CH2+.CH3 + 2e m/z = 58 Fragmentation of M+ producing 43 CH3CH2CH2+CH3 CH3CH2CH2+ + CH3 m/z = 43m/z = 15Ionization and FragmentationWill MOVE (ACCELARATED)Unpair electronNOT movem/z = 58 Fragmentation of M producing 29 CH3CH2+CH2CH3 CH3CH2+ + .CH2CH3 +m/z = 29 Fragmentation of M+ producing 15 CH3CH2CH2+CH3 CH3CH2CH2 + +CH3Positively chargedIonization forming M+ CH3CH2:CH2CH3 + e CH3CH2+CH2CH3 + 2e 26. Ionization/ Fragmentation pattern for CH3CH2CH2CH3 CH3CH2CH2CH3IonizationCH3CH2CH2CH3+ CH3CH2CH2+CH3+CH3CH2+CH3CH2CH2CH3+- 58 - m/z highest deflect LEAST CH3CH2CH2+ 43 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOSTCH3+ Deflect MOSTCH3CH2CH2CH3+ Deflect LEAST 27. Ionization/ Fragmentation pattern for CH3CH2CH2CH3 CH3CH2CH2CH3IonizationCH3CH2CH2CH3+ CH3CH2CH2+CH3+CH3CH2+CH3CH2CH2CH3+- 58 - m/z highest deflect LEAST CH3CH2CH2+ 43 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOSTCH3+Ionization and Fragmentation Process CH3CH2CH2CH3IonizationIonization of CH3CH2CH2CH3 CH3CH2CH2CH3 + e CH3CH2CH2CH3+ + 2e 58 or CH3CH2:CH2CH3 + e CH3CH2+CH2CH3 + 2e 58CH3CH2CH2CH3+Deflect MOSTFragmentationMass spectrum CH3CH2CH2CH3Fragmentation of M+ CH3CH2CH2+CH3 CH3CH2CH2+ - 43 CH3CH2+CH2CH3 CH3CH2+ CH3CH2CH2+CH3 +CH3Deflect LEAST 29 - 15CH3CH2CH2CH3+- 58 - m/z highest deflect LEAST CH3CH2CH2+ 43 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST 28. Ionization/ Fragmentation pattern CH3CH(CH3)CH2CH3CH3CH(CH3)CH2CH3+IonizationCH3CH(CH3)CH2CH3+CH3CH(CH3)CH2+ CH3CH2+CH3CH(CH3)+ CH3+CH3CH(CH3)CH2CH3+- 72 - m/z highest deflect LEAST CH3CH(CH3)CH2+ 57 CH3CH(CH3)+ - 43 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST15CH3+ Deflect MOSTCH3CH(CH3)CH2CH3+ Deflect LEAST 29. Ionization/ Fragmentation pattern CH3CH(CH3)CH2CH3CH3CH(CH3)CH2CH3+IonizationCH3CH(CH3)CH2CH3+CH3CH(CH3)CH2+ CH3CH2+CH3CH(CH3)+ CH3+CH3CH(CH3)CH2CH3+- 72 - m/z highest deflect LEAST CH3CH(CH3)CH2+ 57 CH3CH(CH3)+ - 43 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST15CH3+Ionization and Fragmentation Process CH3CH(CH3)CH2CH3IonizationIonization of CH3CH(CH3)CH2CH3CH3CH(CH3)CH2CH3 + e CH3CH(CH3)CH2CH3 + + 2e 72 or CH3CH(CH3)CH2CH3 + e CH3CH(CH3)CH2+.CH3+ 2e 72 or CH3CH(CH3)CH2CH3 + e CH3CH(CH3)+.CH2CH3 + 2e 72Deflect MOSTFragmentation Fragmentation of M+ CH3CH(CH3)CH2+ - 57 CH3CH(CH3)+ 43 CH3CH2+ 29 CH3+ - 15CH3CH(CH3)CH2CH3+ Deflect LEASTMass spectrum CH3CH(CH3)CH2CH3 CH3CH(CH3)CH2CH3+- 72 - m/z highest deflect LEAST CH3CH(CH3)CH2+ 57 CH3CH(CH3)+ - 43 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST 30. Ionization/ Fragmentation pattern for CH3CH2CH2OH CH3CH2CH2OHIonizationCH3CH2CH2OH+CH2CH2OH+CH3CH2+CH2OH+CH3 +CH3CH2CH2OH+- 60 - m/z highest deflect LEAST CH2CH2OH+ 45 CH2OH+ - 31 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST15CH3+ Deflect MOST60CH3CH2CH2OH+ Deflect LEAST 31. Ionization/ Fragmentation pattern for CH3CH2CH2OH CH3CH2CH2OHIonizationCH3CH2CH2OH+CH2CH2OH+CH3CH2+CH2OH+CH3 +CH3CH2CH2OH+- 60 - m/z highest deflect LEAST CH2CH2OH+ 45 CH2OH+ - 31 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST6015CH3+Ionization and Fragmentation Process CH3CH2CH2OHIonizationIonization of CH3CH2CH2OH CH3CH2CH2OH + e CH3CH2CH2OH+ + 2e 60 or CH3CH2CH2OH + e CH3CH2+. CH2OH + 2e 60CH3CH2CH2OH+Deflect MOSTFragmentationDeflect LEASTMass spectrum CH3CH2CH2CH3Fragmentation of M+ CH3+.CH2CH2OH +CH2CH2OH - 45 CH3CH2+CH2OH +CH2OH 31CH3CH2+CH2OH CH3CH2+ 29CH3+.CH2CH2OH +CH3CH3CH2CH2OH+- 60 - m/z highest deflect LEAST CH2CH2OH+ 45 CH2OH+ - 31 CH3CH2+ 29 CH3+ 15 - m/z lowest deflect MOST- 151560 32. Ionization/ Fragmentation pattern C(CH3)4 C(CH3)4+Ionization(C(CH3)4)C(CH3)3+ C(CH3)+ C(CH3)4+ C(CH3)3+ C(CH3)2+ C(CH3)+ CH3+CH3+ Deflect MOSTC(CH3)2+ CH3+- 72 - m/z highest deflect LEAST 57 - 42 27 15 - m/z lowest deflect MOST(C(CH3)4)+ Deflect LEAST 33. Ionization/ Fragmentation pattern C(CH3)4 C(CH3)4+Ionization(C(CH3)4)C(CH3)3+C(CH3)2+C(CH3)+ C(CH3)4+ C(CH3)3+ C(CH3)2+ C(CH3)+ CH3+C(CH3)4IonizationIonization of C(CH3)4C(CH3)4 + e C(CH3)4++ 2e 72Deflect MOSTFragmentation Fragmentation of M+ C(CH3)3+ 57 C(CH3)2+ - 42 C(CH3)+ 27 CH3+ 15- 72 - m/z highest deflect LEAST 57 - 42 27 15 - m/z lowest deflect MOST(C(CH3)4)+CH3+Ionization and Fragmentation ProcessCH3+Deflect LEASTMass spectrum C(CH3)4 C(CH3)4+ C(CH3)3+ C(CH3)2+ C(CH3)+ CH3+- 72 - m/z highest deflect LEAST 57 - 42 27 15 - m/z lowest deflect MOST 34. Ionization/ Fragmentation pattern CH3(CH2)8CH3 CH3(CH2)8CH3IonizationCH3(CH2)8CH3+ CH3(CH2)8CH3+ = 142 - m/z highest deflect LEAST CH3(CH2)7CH2+ = 127 CH3(CH2)6CH2+ = 113 CH3(CH2)5CH2+ = 99 CH3(CH2)4CH2+ = 85 CH3(CH2)3CH3+ = 71 CH3(CH2)2CH2+ = 57 CH3CH2CH2+ = 43 CH3CH2+ = 29 CH3+ = 15 m/z lowest deflect MOSTCH3+ Deflect MOSTCH3(CH2)8CH3+ Deflect LEAST 35. Ionization/ Fragmentation pattern CH3(CH2)8CH3 CH3(CH2)8CH3IonizationCH3(CH2)8CH3+ CH3(CH2)8CH3+ = 142 - m/z highest deflect LEAST CH3(CH2)7CH2+ = 127 CH3(CH2)6CH2+ = 113 CH3(CH2)5CH2+ = 99 CH3(CH2)4CH2+ = 85 CH3(CH2)3CH3+ = 71 CH3(CH2)2CH2+ = 57 CH3CH2CH2+ = 43 CH3CH2+ = 29 CH3+ = 15 m/z lowest deflect MOSTCH3+CH3(CH2)8CH3+Deflect MOSTDeflect LEASTIonization and Fragmentation Process CH3(CH2)8CH3IonizationIonization of CH3(CH2)8CH3 CH3(CH2)8CH3 + e CH3(CH2)8CH3+ + 2e 142Fragmentation CH3(CH2)7CH2+ = 127 CH3(CH2)6CH2+ = 113 CH3(CH2)5CH2+ = 99 CH3(CH2)4CH2+ = 85 CH3(CH2)3CH3+ = 71 CH3(CH2)2CH2+ = 57 CH3CH2CH2+ = 43 CH3CH2+ = 29 CH3+ = 15Mass spectrum CH3(CH2)8CH3 Loss of methylene gp, CH2 = 14 36. Ionization/ Fragmentation pattern CH3(CH2)8CH3 C6H5CH2OHIonizationC6H5CH2OH+C6H5CH2OH+ C6H5CH2+ C6H5+ CH2OH+ OH+= 108 - m/z highest deflect LEAST = 91 = 77 = 31 = 17 m/z lowest deflect MOSTC6H5CH2OH+OH+ Deflect MOSTDeflect LEAST 37. Ionization/ Fragmentation pattern CH3(CH2)8CH3 C6H5CH2OHIonizationC6H5CH2OH+C6H5CH2OH+ C6H5CH2+ C6H5+ CH2OH+ OH+= 108 - m/z highest deflect LEAST = 91 = 77 = 31 = 17 m/z lowest deflect MOSTC6H5CH2OH+ Deflect LEASTOH+ Deflect MOSTIonization and Fragmentation ProcessC6H5CH2OHIonizationIonization of C6H5CH2OH C6H5CH2OH + e C6H5CH2OH+ + 2e 108Fragmentation C6H5CH2+ C6H5+ CH2OH+ OH+= 91 = 77 = 31 = 17Mass spectrum CH3(CH2)8CH3 C6H5CH2OH+ C6H5CH2+ C6H5+ CH2OH+ OH+= 108 - m/z highest deflect LEAST = 91 = 77 = 31 = 17 m/z lowest deflect MOST 38. Presence of IsotopesIonization/ Fragmentation pattern molecule CI2 CI2moleculeIonization35CI-35CI+35CI+35CI-37CI+37CI-37CI+37CI+37CI-37CI- 74 - m/z highest deflect LEAST 72 35CI-35CI 70 37CI 37 35CI 35 - m/z lowest deflect MOST 35CI-37CI35CI+37CI-37CI+Deflect MOSTDeflect LEAST 39. Presence of IsotopesIonization/ Fragmentation pattern molecule CI2 CI2moleculeIonization35CI-35CI+35CI+35CI-37CI+37CI-37CI+37CI+37CI-37CI- 74 - m/z highest deflect LEAST 72 35CI-35CI 70 37CI 37 35CI 35 - m/z lowest deflect MOST 35CI-37CI35CI+37CI-37CI+Deflect MOSTDeflect LEASTIonization and Fragmentation Process CI2 moleculeIonization Ionization of CI2 to CI2+ CI:CI + e- [35CI+.35CI] + 2e 70 CI:CI + e- [35CI+.37CI] + 2e 72 CI:CI + e- [37CI+.37CI] + 2e 74Ratio (35CI35CI:CI37CI:3537CI37CI) - 9:6:1Fragmentation Fragmentation of CI2+ into CI+ CI+.CI [35CI+ + 35CI] + 2e 35 m/z = 35CI .CI [37CI+ + +m/z = 3737CI] + 2e 37Ratio (35CI : 37CI) - 3:1Mass spectrum CI2 / CI atoms 37CI-37CI- 74 - m/z highest deflect LEAST 72 35CI-35CI 70 37CI 37 35CI 35 - m/z lowest deflect MOST 35CI-37CI 40. Presence of IsotopesIonization/ Fragmentation pattern molecule Br2 Br2moleculeIonization79Br-79Br+79Br+79Br-81Br+81Br-81Br+81Br+81Br-81Br- 162 - m/z highest deflect LEAST 160 79Br-79Br 158 81Br 81 79Br 79 - m/z lowest deflect MOST 79Br-81Br79Br+Deflect MOST81Br-81Br+Deflect LEAST 41. Presence of IsotopesIonization/ Fragmentation pattern molecule Br2 Br2moleculeIonization79Br-79Br+79Br+79Br-81Br+81Br-81Br+81Br+81Br-81Br- 162 - m/z highest deflect LEAST 160 79Br-79Br 158 81Br 81 79Br 79 - m/z lowest deflect MOST 79Br-81Br79Br+Deflect MOSTIonization and Fragmentation Process Br2 moleculeIonization Ionization of Br2 to Br2+ Br:Br + e- [81Br+.81Br] + 2e 162 Br:Br + e- [79Br+.81Br] + 2e 160 Br:Br + e- [79Br+.79Br] + 2e 158Fragmentation Fragmentation of Br2+ to Br+ Br+.Br [81Br+ + 81Br] 81 m/z = 81Br+.Br [79Br+ + 79Br] 79 m/z = 79Ratio (79Br79Br:Br81Br:79Br81Br) 1:2:181Ratio (79Br : 81Br) - 1:181Br-81Br+Deflect LEASTMass spectrum Br2 / Br atoms 81Br-81Br- 162 - m/z highest deflect LEAST 160 79Br-79Br 158 81Br 81 79Br 79 - m/z lowest deflect MOST 79Br-81Br 42. Presence of IsotopesIonization/ Fragmentation pattern CH3CH(CI)CH3 CH3CH(CI)CH3CH3CH(CI)CH3+IonizationCH3CH(37CI)CH3+ CH3CH(35CI)CH3+ CH3CH(37CI)+ CH3CH(35CI)+ CH3CHCH3+ CH3C +CH3C+ Deflect MOST= 80 - m/z highest deflect LEAST = 78 = 65 = 63 = 43 = 27 - m/z lowest deflect MOSTCH3CH(CI)CH3+ Deflect LEAST 43. Presence of IsotopesIonization/ Fragmentation pattern CH3CH(CI)CH3 CH3CH(CI)CH3CH3CH(CI)CH3+IonizationCH3CH(37CI)CH3+ CH3CH(35CI)CH3+ CH3CH(37CI)+ CH3CH(35CI)+ CH3CHCH3+ CH3C +CH3C+= 80 - m/z highest deflect LEAST = 78 = 65 = 63 = 43 = 27 - m/z lowest deflect MOSTCH3CH(CI)CH3+Deflect MOSTDeflect LEASTIonization and Fragmentation ProcessCH3CH(CI)CH3IonizationIonization CH3CH(CI)CH3 CH3CH(CI)CH3+ e CH3CH(CI)CH3+ + 2e 78/80Fragmentation CH3CH(37CI)+ CH3CH(35CI)+ CH3CHCH3+ CH3C += 65 = 63 = 43 = 27Presence of M+ and (M++ 2) peakIsotopic peak = 63CH3CH(35CI)+Isotopic peak = 65CH3CH(37CI)+Isotopic peak (M+)= 78CH3CH(35CI)CH3Presence isotope 35CI and 37CIIsotopic peak (M++2) = 80CH3CH(37CI)CH3 44. Ionization/ Fragmentation pattern CH3CH2CH3Br CH3CH2CH2BrPresence of IsotopesCH3CH2CH2Br+IonizationCH3CH2CH281Br+ = 124 - m/z highest deflect LEAST CH3CH2CH279Br + = 122 CH2CH281Br+ = 109 CH2CH279Br+ = 107 CH281Br+ = 95 CH279Br+ = 93 CH3CH2CH2+ = 43 CH3C + = 27 - m/z lowest deflect MOSTCH3C+ CH3 + Deflect MOST C Deflect MOSTCH3CH2CH2Br+ CH3CH2 Deflect LEASTCH2Br+ Deflect LEAST 45. Presence of IsotopesIonization/ Fragmentation pattern CH3CH2CH3Br CH3CH2CH2BrCH3CH2CH2Br+IonizationCH3CH2CH281Br+ = 124 - m/z highest deflect LEAST CH3CH2CH279Br + = 122 CH2CH281Br+ = 109 CH2CH279Br+ = 107 CH281Br+ = 95 CH279Br+ = 93 CH3CH2CH2+ = 43 CH3C + = 27 - m/z lowest deflect MOSTCH3C+ CH3 + Deflect MOST CCH3CH2CH2Br+ CH3CH2 Deflect LEASTCH2Br+Deflect MOSTDeflect LEASTIonization and Fragmentation Process CH3CH2CH3BrIonizationIonization CH3CH2CH2Br CH3CH2CH2Br + e CH3CH2CH2Br+ + 2e 122/124Fragmentation CH2CH281Br+ = 109 CH2CH279Br+ = 107 CH281Br+ = 95 CH279Br+ = 93 CH3CH2CH2+ = 43 CH3C + = 27Presence of M+ and (M++ 2) peakIsotopic peak = 107CH2CH279BrIsotopic peak = 109Isotopic peak (M+)= 122Isotopic peak (M++2) = 124CH2CH281BrCH3CH2CH279BrCH3CH2CH281BrPresence isotope 79Br and 81Br 46. Isomers, Propan-1-ol vs Propan-2-olIsomers of C3H8OHPropan-2-olPropan-1-olCH3CH2CH2OHOH | CH3CHCH3VsMolecular Ion, M+ = 60 -> CH3CH2CH2OH+Molecular Ion, M+ = 60 -> CH3CH(OH)CH3+Fragmentation peaksFragmentation peaksLoss of CH3(M - 15)+ = 45 -> (CH2CH2OH)+Loss of CH3(M - 15)+ = 45 -> (CH3CH(OH))+Loss of CH3CH2(M - 29)+ =31 -> (CH2OH)+Loss of OH(M - 17)+ = 43 -> (CH3CHCH3)+Loss of CH2OH(M - 31)+ = 29 -> (CH3CH2)+Loss of OH, CH3, H(M - 33)+ = 27 -> (CH3C)+Loss of CH2CH2OH(M - 45)+ =15 -> (CH3)+Vs15 47. Isomers, Propan-1-ol vs Propan-2-olIsomers of C3H8OHPropan-2-olPropan-1-olCH3CH2CH2OHOH | CH3CHCH3VsMolecular Ion, M+ = 60 -> CH3CH2CH2OH+Molecular Ion, M+ = 60 -> CH3CH(OH)CH3+Fragmentation peaksFragmentation peaksLoss of CH3(M - 15)+ = 45 -> (CH2CH2OH)+Loss of CH3(M - 15)+ = 45 -> (CH3CH(OH))+Loss of CH3CH2(M - 29)+ =31 -> (CH2OH)+Loss of OH(M - 17)+ = 43 -> (CH3CHCH3)+Loss of CH2OH(M - 31)+ = 29 -> (CH3CH2)+Loss of OH, CH3, H(M - 33)+ = 27 -> (CH3C)+Loss of CH2CH2OH(M - 45)+ =15 -> (CH3)+Vs15Peak 29 and 31 are found Inductive effect of OH causes splitting of CH3CH2-|-CH2OH m/z =29 peak detected CH2CH3 present CH3CH2 + CH2OH CH3CH2 + + CH2OH m/z= 29CH3CH2 + CH2OH CH3CH2 + +CH2OH m/z= 31Peak 45 is higher Loss of methyl radical at both sides produce (CH3CH(OH))+ No m/z= 29 peak detected No CH2CH3 found ! OH OH | | CH3 C+CH3 CH3C+ + CH3 | | H H m/z= 45 48. Isomers, 2 methylbutane vs 2, 2 dimethylpropane 2, 2 dimethylpropaneIsomers of C5H12CH3 | CH3C-CH3 | CH32 methylbutaneCH3 | CH3CHCH2CH3VsMolecular Ion, M+ = 72 -> CH3CH(CH3)CH2CH3+Molecular Ion, M+ = 72 -> C(CH3)4+Loss of CH3Fragmentation peaks (M - 15)+ = 57 -> CH3CH(CH3)CH2+Loss of CH3Fragmentation peaks (M - 15)+ = 57 -> C(CH3)3+Loss of CH3CH2(M - 29)+ =43 -> CH3CH(CH3)+Loss of TWO CH3(M - 30)+ = 42 -> C(CH3)2+Loss of CH3CH(CH3)(M - 43)+ = 29 -> CH3CH2+Loss of THREE CH3(M - 45)+ = 27 -> CH3C+Loss of CH3CH(CH3)CH2(M - 57)+ = 15 -> CH3+Loss of C(CH3)3(M - 57)+ = 15 -> CH3+Vs 49. Isomers, 2 methylbutane vs 2, 2 dimethylpropane 2, 2 dimethylpropaneIsomers of C5H12CH3 | CH3C-CH3 | CH32 methylbutaneCH3 | CH3CHCH2CH3VsMolecular Ion, M+ = 72 -> CH3CH(CH3)CH2CH3+Molecular Ion, M+ = 72 -> C(CH3)4+Loss of CH3Fragmentation peaks (M - 15)+ = 57 -> CH3CH(CH3)CH2+Loss of CH3Fragmentation peaks (M - 15)+ = 57 -> C(CH3)3+Loss of CH3CH2(M - 29)+ =43 -> CH3CH(CH3)+Loss of TWO CH3(M - 30)+ = 42 -> C(CH3)2+Loss of CH3CH(CH3)(M - 43)+ = 29 -> CH3CH2+Loss of THREE CH3(M - 45)+ = 27 -> CH3C+Loss of CH3CH(CH3)CH2(M - 57)+ = 15 -> CH3+Loss of C(CH3)3(M - 57)+ = 15 -> CH3+VsPeak 29 absent CH3CH2 presentPeak 29 absent No CH3CH2 Peak 57 is higher Loss of methyl radical produce tertiary carbocation Tertiary carbocation More stableCH3 | CH3C+CH3 | CH3CH3 | CH3 C+ + CH3 | CH3 m/z= 57 50. Normal Mass Spectrometer Vs High Resolution Mass spectrometerHigh Resolution Mass SpectrometerNormal Mass Spectrometer Molecular formula/weight by adding all relative atomic mass RMM for molecule = Sum of all RAM RMM O2 = 16 + 16 = 32 RMM N2H4 = (14 x 2) + (1 x 4) = 32 RMM CH3OH = (12 + 3 + 16 + 1) = 32 Molecular ion peak -O2, N2H4, CH3OH -RAM, O = 16 RAM, N = 14 RAM, H = 1 RAM, C = 12VsSAME = 32O2, N2H4, CH3OHMeasure to RMM to 4/5 decimal places RAM, O = 15.9949 Molecular formula/weight RAM, N = 14.0031 by adding all relative atomic mass RAM, H = 1.0078 RMM for molecule = Sum of all RAM RAM, C = 12.0000 RMM O2 = 15.9949 + 15.9949 = 31.9898 RMM N2H4 = (14.0031 x 2) + (1.0078 x 4) = 32.0375 RMM CH3OH = (12.0000 )+ (3 x 1.0078) + 15.9949 = 32.0262 Molecular ion peak- O2, N2H4, CH3OH is the NOT the sameO2Vs same differentN2H4CH3OH 51. Normal Mass Spectrometer Vs High Resolution Mass spectrometerHigh Resolution Mass SpectrometerNormal Mass Spectrometer Molecular formula/weight by adding all relative atomic mass RMM for molecule = Sum of all RAM RMM O2 = 16 + 16 = 32 RMM N2H4 = (14 x 2) + (1 x 4) = 32 RMM CH3OH = (12 + 3 + 16 + 1) = 32 Molecular ion peak -O2, N2H4, CH3OH -RAM, O = 16 RAM, N = 14 RAM, H = 1 RAM, C = 12VsSAME = 32Measure to RMM to 4/5 decimal places RAM, O = 15.9949 Molecular formula/weight RAM, N = 14.0031 by adding all relative atomic mass RAM, H = 1.0078 RMM for molecule = Sum of all RAM RAM, C = 12.0000 RMM O2 = 15.9949 + 15.9949 = 31.9898 RMM N2H4 = (14.0031 x 2) + (1.0078 x 4) = 32.0375 RMM CH3OH = (12.0000 )+ (3 x 1.0078) + 15.9949 = 32.0262 Molecular ion peak- O2, N2H4, CH3OH is the NOT the sameO2, N2H4, CH3OHO2N2H4Vs same differentHigh resolution Mass spectrum data Video how MS workshttp://www.absciex.com/CH3OH 52. IB Questions on Mass Spectrometer 1Mass spectrometer used to investigate isotopic composition of elements. Thallium has two isotopes shown below. 203 81205TI81TI1) State symbol of two singly charged ions form.2) State which ion will follow path marked X on diagram.3) Doubly charged ions form. Suggest reason whether they would be deflected less than or more than ions at X and Y.Naturally occuring boron has 2 isotopes, shown below. RAM of boron is 10.81. 10B11BB% abundance x% (100 x)% Determine percentage abundance of these isotopes. 10B11B 53. IB Questions on Mass Spectrometer 1Mass spectrometer used to investigate isotopic composition of elements. Thallium has two isotopes shown below. 203 81205TI81TI1) State symbol of two singly charged ions form. 20320581812) State which ion will follow path marked X on diagram.X=203 81lighter -> DEFLECTED MORE3) Doubly charged ions form. Suggest reason whether they would be deflected less than or more than ions at X and Y. DEFLECTED MORE. Cause deflection depends on m/z ratio. Low Mass + High charge -> m/z ratio is low -> deflected more. Naturally occuring boron has 2 isotopes, shown below. RAM of boron is 10.81. 1011BBB% abundance x% (100 x)% Determine percentage abundance of these isotopes. Answer: Let % abundance be x. Relative Isotopic Mass: 10101119% B81% B11= (Mass B x % Abundance) + (Mass B x % Abundance) = (10 x x/100) + (11 x (100 x)/100) = 10.81 X = 19% 54. IB Questions on Mass Spectrometer 2A sample of germanium is analysed in mass spec. The first and last processes are vaporization and detection. 1) State the names of other three processes in order in which they occur2) For each of the processes named in a (i), outline how the process occur3) Sample of germanium found to have following compositioni)Define relative atomic mass.ii) Calculate RAM of sample, giving answer to two decimal places. 55. IB Questions on Mass Spectrometer 2A sample of germanium is analysed in mass spec. The first and last processes are vaporization and detection. 1) State the names of other three processes in order in which they occur Answer: Ionization -> Acceleration -> Deflection 2) For each of the processes named in a (i), outline how the process occur Ionization -> Sample bombarded with high energy/high speed electrons Acceleration -> Cations (+ve charged ions) accelerated by an electric field Deflection -> Cations deflected by a magnetic field 3) Sample of germanium found to have following compositioni)Define relative atomic mass. Average / weighted masses of all isotopes of an element. ii) Calculate RAM of sample, giving answer to two decimal places. Relative Isotopic Mass = (Mass x % Abundance) + (Mass x % Abundance) + (Mass 74Ge x % Abundance) + (Mass 76Ge x % Abundance) 19% 81% = (70 x 22.60/100) + (72 x 25.45/100) + (74 x 36.73/100) + (76 x 15.22/100) = 72.89 70Ge72Ge 56. IB Questions on Mass Spectrometer 3The following shows a mass spectrometer. 1)Identify the parts labelled A, B and C.ACB2)State and explain which one of the following will undergo greatest deflection.3) Mass spectrum for an element shown below: i) Explain why there is more than one peak.ii) Calculate the relative atomic mass of the element. 57. IB Questions on Mass Spectrometer 3The following shows a mass spectrometer. 1)Identify the parts labelled A, B and C. electron gun ionisation chamber ionizerC Electric field Charged plates Potential differenceB Magnetic field Magnet ElectromagnetA2)State and explain which one of the following will undergo greatest deflection.Answer : Greatest deflection -> lowest mass + highest charged -> m/z -> lowest 7Li+6Li2+smallest deflection high mass, low chargedgreatest deflection low mass, high charged3) Mass spectrum for an element shown below: i) Explain why there is more than one peak. Existence of isotopes ii) Calculate the relative atomic mass of the element. Relative Isotopic Mass= (Mass 24Y x % Ab) + (Mass 25Y x % Ab) + (Mass 26Yx % Ab) = (24 x 79/100) + (25 x 10/100) + (26 x 11/100) = 24.32 58. IB Questions on Mass Spectrometer 4Vaporized magnesium is introduced into mass spec. One of the ions that reaches detector shown below. 25Mg+12 1)Identify the number of protons, neutron and electrons2) State how this ion is accelerated in mass spectrometer.3) The ion25Mg2+is also detected by changing the magnetic field. Deduce and explain by reference tom/z values of these two ions of magnesium, which of the ions magnetic field.25Mg2+and25Mg+is detected using a stronger 59. IB Questions on Mass Spectrometer 4Vaporized magnesium is introduced into mass spec. One of the ions that reaches detector shown below. 25Mg+12 1)Identify the number of protons, neutron and electrons Answer : 12 protons, 13 neutrons, 11 electrons2) State how this ion is accelerated in mass spectrometer. Using a strong electric field/strong opposite charged plate/potential differenceCations (+ve) accelerated by (-ve) plates25Mg2+3) The ionis also detected by changing the magnetic field. Deduce and explain by reference tom/z values of these two ions of magnesium, which of the ions magnetic field. Answer:25Mg+25Mg2+and25Mg+is detected using a stronger- due to lower charge -> m/z is higher -> deflected less -> needs a stronger magnetic field to deflect.25Mg+smallest deflection high mass, low chargedStrong magnet/magnetic field to deflect it to bottom 60. IB Questions on Mass Spectrometer 5Rubidium contains two stable isotopes shown below. RAM for rubidium is 85.47 85Rb87Rb1)Calculate % of each isotope in rubidium.2) Vaporized sample is ionized and accelerated in a mass spec. How the use of magnetic field and detector enables the percentage of two isotopes to be determined.Detector Magnetic field/Deflector 61. IB Questions on Mass Spectrometer 5Rubidium contains two stable isotopes shown below. RAM for rubidium is 85.47 8587RbRb1)Calculate % of each isotope in rubidium. Answer : Let % abundance be x %. 85Rb% Abundancex%87RbRb(100 x)%Relative Isotopic Mass: = (Mass 85Rb x % Abundance) + (Mass 87Rb x % Abundance) = (85 x x/100) + (87 x (100 x)/100) = 85.47 1) = 76.5% X85Rb76.5%87Rb23.5%2) Vaporized sample is ionized and accelerated in a mass spec. How the use of magnetic field and detector enables the percentage of two isotopes to be determined.Detector Magnetic field/Deflector M+ ions deflected by magnetic field 85- lighter -> deflected more87- heavier -> deflected lessRb Rb Convert abundance M+ ions to electrical current. M+ ions neutralize by electrons (more e needed - higher current higher intensity of peak) Ratio of intensity peaks show ratio of ions in sample Ratio of height of peaks due to 85Rb : 87Rb > 76.5 : 23.5 62. Acknowledgements Thanks to source of pictures and video used in this presentation http://serc.carleton.edu/research_education/geochemsheets/techniques/gassourcemassspec.html http://www.mhhe.com/physsci/chemistry/carey/student/olc/ch13ms.html http://science.howstuffworks.com/mass-spectrometry3.htmThanks to Creative Commons for excellent contribution on licenses http://creativecommons.org/licenses/Prepared by Lawrence Kok Check out more video tutorials from my site and hope you enjoy this tutorial http://lawrencekok.blogspot.com