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

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Introduction product ions. The peak assignment based on a comparison of ion mobility spectra with spectra obtained by CI-MS whereas (M-3H) + and (M-3) + H 2 O were identified by using APCI-MS with 63 Ni ionisation. A Recent study by Marotta and Paradisi obtained an array of low boiling point linear and branched C 5 -C 8 alkane ions by using air plasma fed APCI-MS. 79 Subsequent chemical ionisation (CI) studies showed that intact high mass alkane ions could be generated in the gas phase by using ligated-metal ion chemistry via cationization methods (silver cation Ag + , disilver-oxide cation Ag 2 O + ) or transition metals ( Fe,Co,Ni). 84-86 Moreover organometallic cations were used by Byrd et al. 87 in particular cobalt cyclopentadienyl cation (CpCo •+ ) to create intact gas phase species [(CpCo+alkane)-2H 2 ] •+ . Some of these ions were used to determine the molecular weight (MW) of many nonpolar hydrocarbons and polymers and were later incorporated into other techniques for petroleum analysis. However the most extensive work in the field of nonpolar hydrocarbon analysis within model mixtures or real life complex mixtures is attributed to Kenttamaa et.al. The group explored many revolutionised and efficient methodologies to explain the complex compositions of crude oil, asphaltenes and lubricants. 28,88,89 An analytical summary assay of their work in the recent years will be portrayed. The work of Kenttamaa’s group is described to be an intriguing contribution to this field. They mainly adopted laser desorption/ionisation methods using laser induced acoustic desorption. 90-92 This enabled them to desorp non-volatile and thermally labile species as intact neutral species into the gas phase. Such an approach allows independent control of desorption/ionisation processes. This forms a benefit which is not feasible with other techniques. More recently this group has examined the behaviour of hydrocarbon ions in different mass spectrometries using different ionisation technologies. For example, Kenttamaa et al. utilized cyclopentadienyl cobalt radical cation (CpCo •+ ) as an ionising agent for the analysis of various polar and nonpolar components in petroleum distillates using laser-induced acoustic desorption/fourier transform ion cyclotron resonance mass spectrometry (LIAD/FT ICR-MS). 28,93 The neutral desorbed hydrocarbons were reacted with activated CpCo •+ to produce stable addition products (adduct-H 2 , adduct-2H 2 , or both 15
Introduction products). Other molecules reacted by loss of methyl radical and two hydrogen molecules like 5-α-cholestane. This group applied the same LIAD/CpCo •+ CI method in another study for polyethylene (PE) samples with low molecular weight (200-655). 94 Later on Kenttamaa co-workers selected a less aggressive chemical ionisation reagent, the water cluster of Manganese cation, [ClMn(H 2 O) + ], combined with LIAD for examining a variety of hydrocarbons. 95 This ion was useful to ionise all types of hydrocarbons forming only one product ion [ClMn+M] + via water loss and without fragmentation. This latter method was described to be an efficient mass spectrometric method for the analysis of branched saturated hydrocarbons forming exclusively pseudomolecular ions (adduct-H 2 O). Such ionisation was found better characterising than atmospheric pressure chemical ionisation (APCI) and ESI of nonpolar lipids and steroids as according to their observations. 96 Another LIAD/ClMn(H 2 O) + method was applied for the analysis of base oils (major components of Lubricants). 88 The product ion [ClMn+M] + was the only ion representing each components (M) within the complex mixture of the base oil as shown in Scheme 1. The molecular weight distribution for base oil samples was found in the range of 350-600 Da. ClMn(H 2 O) + + M H 2 O [ClMn+M] + Scheme 1. Generation of adduct ions using LIAD/ClMn(H 2 O) + Coupling LIAD to APCI by kenttamaa’s group enabled the evaporation and ionisation of polar and nonpolar analytes yielding predominantly molecular ions with minor fragmentation using carbon disulfide (CS 2 ) as a reagent. 97 Protonated molecules (M+H) + were observed to be found in higher branching ratios when benzene was used as APCI reagent. The investigated compounds were structurally similar to those present in petroleum. Petroleum cuts were as a result analysed upon LIAD/APCI using nitrogen gas as the reagent. Explanations were elaborated according to the results of model mixture of the hydrocarbons. Just recently, an APCI/CS 2 method utilized by the same group demonstrated the production of abundant stable molecular ion (M +• ) for nonpolar aromatic, polar aromatic and 16
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 and 28: Introduction Figure 1-2 Range of io
Page 29 and 30: Introduction fractions. 42 Another
Page 31: Introduction 1.3.5 APLI Other crude
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
Page 83 and 84:
Results and Discussion Intens. [%]
Page 85 and 86:
Page 87 and 88:
Results and Discussion isolated fro
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Page 91 and 92:
Page 93 and 94:
Results and Discussion 3.4.5 Tandem
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Page 97 and 98:
Results and Discussion injected int
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Page 101 and 102:
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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Page 115 and 116:
Page 117 and 118:
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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