Development of a Novel Mass Spectrometric ... - Jacobs University

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Introduction review of the work done in this field will be reported. Research efforts have investigated the potential of various ionisation methods to create intact product ions representing the neutral composition of complex mixture. It follows that the choice of ionisation method plays a key role towards a rational detailed analysis of crude oil samples. 1.3.1 EI and CI Traditionally low-energy EI and CI ionisation were used for petroleum analysis. 44- 48 EI (70 eV) produces extensive fragmentation of the ionised hydrocarbon molecules. Nevertheless characteristic fragment ions of petroleum were developed to provide valuable crude oil assay for light or medium hydrocarbons. However, this method can’t be used to identify each type of hydrocarbons as well as it is not accurate if sample contains olefins or heteroatom containing compounds. 49 The obtained molecular weight information becomes rather complicated due to fragmentation and difficulties in identifying molecular ions. Also since molecules are brought to gas phase by thermal vaporisation that defines EI and CI methods, high boiling point molecules of hydrocarbons can’t be detected thereby. 1.3.2 ESI, DESI and MALDI Other soft ionisation techniques such as ESI, APCI, APPI and MALDI have also taken part in the analysis of individual or complex mixtures of hydrocarbons. For numerous applications in mass spectrometry ESI is widely used as an ionisation method. It has been used to evaporate and ionise polar compounds of petroleum containing functional groups with nitrogen or oxygen atom. 41,50-56 The technique can successfully vaporise and ionise hydrocarbon analytes and produce pseudomolecular ions without fragmentation. The molecules in positive molecular ion formation are either protonated (basic compounds) or deprotonated (acidic compounds). With ESI FT ICR combination allows a compact mass spectral display for visual resolution of up to thousands of peaks. However polar hydrocarbons are only a small portion of petroleum (10%). ESI is ‘blind’ to other major nonpolar hydrocarbon fraction of petroleum especially saturate and aromatic 11
Introduction fractions. 42 Another study employed discharge-induced oxidation in desorption electrospray ionisation (DESI). 57 Ambient analysis of saturated hydrocarbons (C 15 H 32 to C 30 H 62 ) using reactive DESI as an insitu derivatization method generated a representative adduct ion for the examined model alkanes and the vacuum gas oil saturate fraction. As well other soft ionisation method were employed for petroleum characterisation, such as MALDI (Figure 1-3). 58,59 A reactive MALDI MS method could successfully ionise large alkanes and polyethylene producing cobalt cyclopentadienyl alkane cation [Co(Cp) 2 (alkane+2H 2 )] +• . This organometallic gas phase chemistry seems functional but nevertheless a selective approach. 60 Figure 1-3 Matrix-assisted laser desorption/ionization (MALDI) 1.3.3 FD and FI Field desorption (FD) and field ionisation (FI) techniques are considered among the most successful ionisation techniques for saturated hydrocarbons. 28 [M-2H] + ions were reported to be abundantly yielded for saturated and aromatic various saturated and aromatic compounds under conditions of field desorption mass 12
Page 1 and 2: Development of a Novel Mass Spectro
Page 3 and 4: Declaration of Authorship I ,Nadim
Page 5 and 6: This work has been carried out unde
Page 7 and 8: Contents Contents Declaration of Au
Page 9 and 10: List of Figures List of Figures Fig
Page 11 and 12: List of Figures Figure 3-39 MS 2 fr
Page 13 and 14: List of Tables List of Tables Table
Page 15 and 16: Abbreviations Abbreviations APCI AP
Page 17 and 18: Abbreviations UV VGOs VOCs VRs ultr
Page 19 and 20: Introduction Analytical chemistry h
Page 21 and 22: Introduction 1.2 Presence and Fate
Page 23 and 24: Introduction aliphatic hydrocarbons
Page 25 and 26: Introduction Figure 1-1 Examples of
Page 27: Introduction Figure 1-2 Range of io
Page 31 and 32: Introduction 1.3.5 APLI Other crude
Page 33 and 34: Introduction products). Other molec
Page 35 and 36: Introduction Other studies performe
Page 37 and 38: Introduction APLI-FT ICR-MS Crude o
Page 39 and 40: Introduction spectrometry in as muc
Page 41 and 42: Introduction catalytic processing t
Page 43 and 44: Introduction Figure 1-6 Kendrick ma
Page 45 and 46: Introduction including determinatio
Page 47 and 48: Introduction 1.5 Scope and Signific
Page 49 and 50: Experimental e) Other model mixture
Page 51 and 52: Experimental 2.2.2 Preparation of O
Page 53 and 54: Experimental 2.4 Graphical Presenta
Page 55 and 56: Results and Discussion experiment.
Page 57 and 58: Results and Discussion Intens. [%]
Page 59 and 60: Results and Discussion common featu
Page 61 and 62: Results and Discussion 3.2 APCI-TOF
Page 63 and 64: Results and Discussion These compou
Page 67 and 68: Results and Discussion Ions were pr
Page 71 and 72: Results and Discussion procedure ba
Page 75 and 76: Results and Discussion to produce m
Page 77 and 78: Results and Discussion 519.5863 519
Page 79 and 80:
Results and Discussion Higher mass
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Results and Discussion Intens. [%]
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Page 85 and 86:
Page 87 and 88:
Results and Discussion isolated fro
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Results and Discussion 3.4.5 Tandem
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Results and Discussion injected int
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Results and Discussion 3.4.8 Quanti
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Results and Discussion Int. x 10000
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Results and Discussion Table 3.6 Qu
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Results and Discussion assessment o
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Results and Discussion hydrocarbons
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Results and Discussion of n-alkanes
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Results and Discussion flow (in I2)
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Results and Discussion Other intere
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Results and Discussion Figure 3-80
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Results and Discussion KMD 2.4 2.2
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Results and Discussion KMD 1.1 1 Le
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Results and Discussion 3.6.4 Asphal
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Conclusions In conclusion we could
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References References 1. Fay, R. M.
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References 23. Colavecchia, M. V.,
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References 47. Dzidic, I., Petersen
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References Hydroconversion Processe
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References 91. Golovlev, V. V., All
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Appendix Light shredder waste Meas.
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419.4592 C 30 H 59 419.4611 4.6 421
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Liqui Moly car motor oil Meas. m/z
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345.3511 C 25 H 45 345.3516 1.5 349
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