No description available.

Fluorinated chemicals have the advantage of both lipophobic and hydrophobic behaviour, leading to broad industrial and commercial use. Fluorosurfactants, for example, are used in applications, such as grease-proofing food packaging, which result in human exposure. Human blood serum, in this work 100 German serum samples dating from 1982 to 2009, is a common matrix for detection of fluorochemicals. Here the most extensive temporal study to date of one class of fluorosurfactant (polyfluoroalkyl phosphate diesters, diPAPs) in human serum is presented. Additionally, another class of fluorosurfactant (sulfonamide-based PAPs, SAmPAPs) was detected in humans for the first time with temporal trends which echo industrial production. Metabolites of diPAPs and SAmPAPs were also quantified, showing temporal trends that relate to the diPAP and SAmPAP levels. Because diPAP and SAmPAP metabolites are environmentally persistent and raise human health concerns, it is important to understand these indirect sources of exposure.

Fluorinated chemicals have the advantage of both lipophobic and hydrophobic behaviour, leading to broad industrial and commercial use. Fluorosurfactants, for example, are used in applications, such as grease-proofing food packaging, which result in human exposure. Human blood serum, in this work 100 German serum samples dating from 1982 to 2009, is a common matrix for detection of fluorochemicals. Here the most extensive temporal study to date of one class of fluorosurfactant (polyfluoroalkyl phosphate diesters, diPAPs) in human serum is presented. Additionally, another class of fluorosurfactant (sulfonamide-based PAPs, SAmPAPs) was detected in humans for the first time with temporal trends which echo industrial production. Metabolites of diPAPs and SAmPAPs were also quantified, showing temporal trends that relate to the diPAP and SAmPAP levels. Because diPAP and SAmPAP metabolites are environmentally persistent and raise human health concerns, it is important to understand these indirect sources of exposure.

Proteins are a highly diversified group of molecules, andfor their study, advanced analytical tools are required. Inparticular, a need for high-throughput techniques has emergedin order to enable the characterization of large sets ofproteins. In this thesis, improved techniques for proteinseparations as well as new tools for the mass spectrometricanalysis of proteins are described. In the work, presented in the first part of the thesis, arefined extract containing proteases from Antarctic krill (Euphausia superba) was separated and characterized bymeans of capillary electrophoresis (CE) and mass spectrometry(MS). Tailored CE separations of the krill extract revealed thepresence of approximately 50 components. In addition, adetailed CE and MS analysis of fractions, containing individualkrill proteases has been carried out. Trypsin-like proteasesfrom krill exhibited a 12-fold and a 60-fold higher digestionefficiency at 37 °C and 2 °C respectively compared todigests performed with bovine trypsin. Furthermore, thecleavage specificity of the trypsin-like proteases wasstudied. In the last part of the thesis, novel concepts forchip-based nanoelectrospray (nanoESI) and matrix-assisted laserdesorption/ionization (MALDI) mass spectrometry are described.First, a micromachined silicon chip with a two-dimensionalmatrix of out-ofplane nanoESI needles for high-throughputanalysis was fabricated. A two-fold improvement insignal-to-noise reproducibility was obtained. Second, achip-based target for MALDI was developed, which featured pairsof elevated 50×50 µm anchors in close proximity. Theanchors were individually addressable with sample solution. Theminiaturized sample preparations at close distance to eachother allowed a simultaneous ionization of a physicallyseparated sample and standard by one single laser pulse. Thisresulted in a twofold reduction of relative mass errors.Moreover, ion suppression of the analyte was significantlyreduced. The effective utilization of the sample resulted in adetection limit of ca 200 zeptomole of angiotensin I. Key words:Proteins, peptides, proteases, Antarctickrill,Euphausia superba, capillary electrophoresis,fluorosurfactants, mass spectrometry, nanoelectrospray, ESI,MALDI, chip, high-throughput, reproducibility, sensitivity andmass accuracy.

<p>Proteins are a highly diversified group of molecules, andfor their study, advanced analytical tools are required. Inparticular, a need for high-throughput techniques has emergedin order to enable the characterization of large sets ofproteins. In this thesis, improved techniques for proteinseparations as well as new tools for the mass spectrometricanalysis of proteins are described.</p><p>In the work, presented in the first part of the thesis, arefined extract containing proteases from Antarctic krill (<i>Euphausia superba</i>) was separated and characterized bymeans of capillary electrophoresis (CE) and mass spectrometry(MS). Tailored CE separations of the krill extract revealed thepresence of approximately 50 components. In addition, adetailed CE and MS analysis of fractions, containing individualkrill proteases has been carried out. Trypsin-like proteasesfrom krill exhibited a 12-fold and a 60-fold higher digestionefficiency at 37 °C and 2 °C respectively compared todigests performed with bovine trypsin. Furthermore, thecleavage specificity of the trypsin-like proteases wasstudied.</p><p>In the last part of the thesis, novel concepts forchip-based nanoelectrospray (nanoESI) and matrix-assisted laserdesorption/ionization (MALDI) mass spectrometry are described.First, a micromachined silicon chip with a two-dimensionalmatrix of out-ofplane nanoESI needles for high-throughputanalysis was fabricated. A two-fold improvement insignal-to-noise reproducibility was obtained. Second, achip-based target for MALDI was developed, which featured pairsof elevated 50×50 µm anchors in close proximity. Theanchors were individually addressable with sample solution. Theminiaturized sample preparations at close distance to eachother allowed a simultaneous ionization of a physicallyseparated sample and standard by one single laser pulse. Thisresulted in a twofold reduction of relative mass errors.Moreover, ion suppression of the analyte was significantlyreduced. The effective utilization of the sample resulted in adetection limit of ca 200 zeptomole of angiotensin I.</p><p><b>Key words:</b>Proteins, peptides, proteases, Antarctickrill,<i>Euphausia superba</i>, capillary electrophoresis,fluorosurfactants, mass spectrometry, nanoelectrospray, ESI,MALDI, chip, high-throughput, reproducibility, sensitivity andmass accuracy.</p>

In this thesis the structure and hydration of small organic and amphipilic compounds adsorbed at the air-liquid interface, have been studied using the nonlinear optical technique Vibrational Sum Frequency Spectroscopy (VSFS). The second order nature of the sum frequency process makes this technique particularly surface sensitive and very suitable for interfacial studies, as molecules at the surface can be distinguished even in the presence of a vast excess of the same molecules in the bulk. Particular emphasis was given to the surface water structure and how it is affected by the presence of small model compounds such as acetic acid and formic acid, and also non-ionic surfactants with sugar based and ethylene oxide based polar headgroups. Understanding the structure of water at these interfaces is of considerable fundamental importance, and here VSFS provided unique information. Upon addition of tiny amounts of these surface active compounds, the ordered surface structure of water was found to be significantly perturbed, as revealed by the changes observed in the characteristic spectroscopic signature of the dangling OH bond of water molecules, which vibrate free in air and are present in the top monolayer. Dramatic differences between the different compounds were also observed in the bonded OH region, providing a valuable insight into the hydration of polar groups at interfaces. Additionally, by employing different polarization combinations of the laser beams involved in the sum frequency process, information about the different water species present at the surface and their average orientation were extracted. In particular an unusual state of water was found with a preferred orientation in a non-donor configuration in close proximity to the hydrophobic region formed by the hydrocarbon tails of the surfactant molecules. The conformation and orientation of the different adsorbates were also characterized, targeting their specific vibrational frequencies. Noteworthy is the orientation of the fluorocarbon chain of ammonium perfluorononanoate (APFN), which in contrast to the hydrocarbon chains of the other surfactant molecules studied, remained constant over a wide range of surface densities. This behaviour was also observed for the anionic headgroup of sodium dodecyl sulphate (SDS). Other interesting findings were the formation of a cyclic dimer bilayer at the surface of concentrated aqueous solutions of acetic acid and the water structuring effect induced by poly(ethylene-oxide) headgroups, in spite of being themselves disordered at the air-liquid interface.

<p>In this thesis the structure and hydration of small organic and amphipilic compounds adsorbed at the air-liquid interface, have been studied using the nonlinear optical technique Vibrational Sum Frequency Spectroscopy (VSFS). The second order nature of the sum frequency process makes this technique particularly surface sensitive and very suitable for interfacial studies, as molecules at the surface can be distinguished even in the presence of a vast excess of the same molecules in the bulk. Particular emphasis was given to the surface water structure and how it is affected by the presence of small model compounds such as acetic acid and formic acid, and also non-ionic surfactants with sugar based and ethylene oxide based polar headgroups. Understanding the structure of water at these interfaces is of considerable fundamental importance, and here VSFS provided unique information. Upon addition of tiny amounts of these surface active compounds, the ordered surface structure of water was found to be significantly perturbed, as revealed by the changes observed in the characteristic spectroscopic signature of the dangling OH bond of water molecules, which vibrate free in air and are present in the top monolayer. Dramatic differences between the different compounds were also observed in the bonded OH region, providing a valuable insight into the hydration of polar groups at interfaces. Additionally, by employing different polarization combinations of the laser beams involved in the sum frequency process, information about the different water species present at the surface and their average orientation were extracted. In particular an unusual state of water was found with a preferred orientation in a non-donor configuration in close proximity to the hydrophobic region formed by the hydrocarbon tails of the surfactant molecules.</p><p>The conformation and orientation of the different adsorbates were also characterized, targeting their specific vibrational frequencies. Noteworthy is the orientation of the fluorocarbon chain of ammonium perfluorononanoate (APFN), which in contrast to the hydrocarbon chains of the other surfactant molecules studied, remained constant over a wide range of surface densities. This behaviour was also observed for the anionic headgroup of sodium dodecyl sulphate (SDS). Other interesting findings were the formation of a cyclic dimer bilayer at the surface of concentrated aqueous solutions of acetic acid and the water structuring effect induced by poly(ethylene-oxide) headgroups, in spite of being themselves disordered at the air-liquid interface.</p>

No description available.