Characterization of complex mixtures of the light shredder waste fraction and caramelization processes by mass spectrometry

  • The analysis of complex mixtures is one of the most challenging areas of analytical chemistry. Within this thesis the composition of two complex mixtures of environmental and food origin, such as the light shredder waste fraction and caramel was studied, respectively. In the last few decades, the light shredder waste fraction has attracted much interest due to the scarcity of space and the toxicological properties of some of its contaminants. In this work, gas chromatography with a flame ionization detector (FID) as well as coupled to mass spectrometry with electron impact (EI) and atmospheric pressure chemical ionization (APCI) has been applied to study the composition of the light shredder waste fraction focusing on non-volatile hydrocarbons. GC-APCI with a time of flight mass analyzer was utilized for the first time in order to determine heavy hydrocarbons of n-alkanes standard and the light shredder waste fraction. Adducts, such as [(M-3H)+H2O]+ and [M-H]+ were found to be the most abundant ions up to n-nonadecane (C19H40) and for higher hydrocarbons established by APCI, respectively. In the second part of this thesis, the composition of caramel, one of the mankind'Engineering and Sciences well-known dietary materials, obtained by the heating of carbohydrates, have been studied. Caramel formed by heating of glucose, fructose, galactose, mannose as well as disaccharides, such as sucrose, lactose and maltose using a conceptually novel combination of mass spectrometric techniques have yielded for the first time an unprecedented account of its chemical composition. The analytical strategy employed uses high-resolution mass spectrometry to identify the most abundant molecular formulas followed by a van Krevelen and Kendrick analysis. A resulting structural hypothesis was further substantiated using targeted LC-tandem MS experiments. The caramelization products include oligomers with up to six carbohydrate units produced through an unselective glycosidic bond formation, dehydration products of oligomers losing up to eight water molecules, hydration products of sugar oligomers, disproportionation and aromatic products. In addition, the molecular formulas of compounds responsible for a brown color of caramel were also proposed. The investigation of thermal decomposition products of pure starch and cellulose as model systems followed by the investigation of bread obtained under comparable conditions has been performed. Commercial caramel products and caramel colors (E 150) were compared with studied carbohydrates. Furthermore, understanding of the composition of roasted coffee beans has been improved by the examination of their carbohydrates fraction.

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Publishing Institution:IRC-Library, Information Resource Center der Jacobs University Bremen
Granting Institution:Jacobs Univ.
Author:Agnieszka Golon
Referee:Nikolai Kuhnert, Gerd-Volker Röschenthaler, Thorsten Dittmar
Advisor:Nikolai Kuhnert
Persistent Identifier (URN):urn:nbn:de:101:1-201307119369
Document Type:PhD Thesis
Date of Successful Oral Defense:2012/11/16
Date of First Publication:2013/02/14
PhD Degree:Chemistry
School:SES School of Engineering and Science
Library of Congress Classification:Q Science / QD Chemistry / QD71-142 Analytical chemistry
Call No:Thesis 2012/53

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