| 1. |
- Chowdhury, Soumitra, 1983-
(author)
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Service Logic in Digitalized Product Platforms : A Study of Digital Service Innovation in the Vehicle Industry
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The digitalization of products has become an important driver for service innovation in manufacturing firms. The embedding of digital technology in previously non-digital products creates digitalized product platforms that enable digital service innovation. Digital service innovation offers new business opportunities for manufacturing industries, as well as challenges established premises for value creation. While digital service innovation can be found in many manufacturing industries, this thesis studies service logic in digitalized product platforms in the vehicle industry.Existing Information Systems (IS) literature presents challenges in digital service innovation relating to value, architecture, and generativity. The design of the architecture of digitalized product platforms requires the identification and combination of digital and non-digital assets. Understanding the architectural aspects is useful in digital service innovation. Moreover, with growing instances of generative digital technologies, it is challenging to develop strategies to leverage generativity for service design in digitalized product platforms. While digital technologies are embedded in products, the role of technology-embeddedness in value creation of digital services is relatively unexplored. Drawing on these challenges, this thesis describes and conceptualizes the underlying premises brought by the architecture and generativity to the value creation of services in digitalized product platforms. The research question addressed in this thesis is: What are the underlying premises for services in digitalized product platforms?To address the question, an interpretive qualitative research approach was adopted in a collaborative research project concerning services enabled by digitalization of vehicles. Drawing on digital innovation and service literature, this thesis presents a theoretical perspective on the role of the architecture and generativity of digitalized product platforms for value creation of digital services. This perspective is conceptualized as underlying premises for this specific class of services. The premises frame the service logic in digitalized product platforms and provide a ground for understanding services in digitalized product platforms in relation to value dimensions, architecture and generativity. The premises are based on five concepts: value-in-architecture, value-in-connectivity, fundamental asset for value creation, mutual dependence of modular and layered modular assets, and re-evaluation of value propositions. The proposed premises offer a basis for understanding value creation of this class of services, and guidance for manufacturing firms designing digitalized product platforms.
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| 2. |
- Lindgren, Thomas, 1973-
(author)
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Recharging Future Mobility : Understanding Digital Anticipatory UX through Car Ethnographies
- 2022
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Doctoral thesis (other academic/artistic)abstract
- Cars have created many positive experiences for people by providing them freedom of mobility, exciting driving thrills and status in society. However, cars are also known to create problems such as pollution, traffic congestion and accidents. To shift towards a more sustainable way of mobility for the future, we need to understand car users' experiences of today and how these shape their anticipation of future mobility.Today users of new cars create their future car using immersive online car configurators, share their anticipation and experiences about the functionality of recent software updates on social media or consider how their future electric car could be charged in a ‘smart’-way through available charging ecosystems. These examples show how digitalisation through new digital technologies extend the ways users anticipate and experience cars as they evolve. These experiences go beyond the moment of in-car interactions, which so far has been the focus for user experience (UX) research and development within academia and industry.UX of digitalised cars is no longer mainly about the experiences of in-car driving and entertainment. Instead, digital technologies expand the possibilities for peoples' anticipation and UX of cars to emerge anywhere and anytime, making human anticipation an important aspect of UX to understand. The forward-oriented decision process, which occurs when people's hopes and fears about the future become part of their present actions and decisions, becomes a strong driver for people's decision making. Therefore, it becomes important to understand anticipation in relation to UX of digitalised cars and for how people shape their futures with cars.Digitalisation of traditional physical products enables a mix of the digital and physical representations of the product, which adds new challenges in how we can understand and research UX of digitalised cars to include more aspects than in the individual moment of physical use, such as people's experiences of anticipating cars. Consequently, my thesis intends to answer the question: How can experiences of anticipating digitalised cars be understood?I have approached the question by studying how digitalisation extends possibilities for UX and anticipation of cars to emerge in everyday life. To investigate the phenomena in everyday settings and follow change over time, a qualitative Design Ethnography (DE) approach was chosen and further developed throughout three different studies. The first study showed experiences of anticipation to be anticipatory, socially constructed, evolving and creating emotional experiences at an online car discussion forum. The second study demonstrated experiences of anticipating autonomous driving (AD) cars to be situated in the social and environmental context, influencing the instant, near and far time spans of people’s anticipation of AD. The third study revealed how electric cars as digital platforms enable people’s anticipation of cars to be related to the surrounding ecosystems. Thus, overall, the thesis consists of five papers that investigate people’s experiences of anticipating digitalised cars from different perspectives.This thesis’s main contribution is directed to UX research in the academic field of Human Computer Interaction (HCI) and the automotive industry. It aims to provide an understanding of how people’s anticipatory experiences of emerging digital technologies related to cars shape new problems and possibilities for future mobility. It concludes that UX research and design needs to be extended to also include aspects of digital representations, evolving functionality and extensions into other ecosystems, which enable the user’s anticipation to emerge and evolve. I have defined this as Digital Anticipatory UX (DAUX), which exposes how people’s anticipation continuously evolves through digi-physical use in the everyday context and creates experience before “use”. By showing a methodological approach to investigate these anticipatory experiences, this thesis also offers a starting point for understanding how people’s evolving hopes and fears can provide insights that implicate the creation of innovative future sustainable mobility solutions with people.
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| 3. |
- Raats, Kaspar, 1981-
(author)
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Towards trustworthy intelligent vehicle technology development
- 2023
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Doctoral thesis (other academic/artistic)abstract
- This thesis addresses the unresolved issues of responsibility and accountability in autonomous vehicle (AV) development, advocating for human-centred approaches to enhance trustworthiness. While AVs hold the potential for improved safety, mobility, and environmental impact, poorly designed algorithms pose risks, leading to public distrust. Trust research focuses on technology-related aspects but overlooks trust within broader social and cultural contexts. Efforts are underway to understand algorithm design practices, acknowledging their potential unintended consequences. For example, Baumer (2017) advocates human-centred algorithm design (HCAD) to align with user perspectives and reduce risks. HCAD incorporates theoretical, participatory, and speculative approaches, emphasising user and stakeholder engagement. This aligns with broader calls for prioritising societal considerations in technology development (Stilgoe, 2013). The research in this thesis responds to these calls by integrating theories on trust and trustworthiness, autonomous vehicle development, and human-centred approaches in empirical investigations guided by the following research question: “How can human-centred approaches support the development of trustworthy intelligent vehicle technology?” This thesis approaches the question through design ethnography to ground the explorations in people’s real-life routines, practices and anticipations and demonstrate how design ethnographic techniques can infuse AV development with human-centred understandings of people’s trust in AVs. The studies reported in this thesis include a) interviews and participatory observations of algorithm designers, b) interviews and probing with residents, and c) staging collaborative, reflective practice through the design ethnographic materials and co-creation with citizens, city, academic and industry stakeholders, including AV algorithm designers. Through these empirical explorations, this thesis suggests an answer to the research question by coining a novel and timely framework for intelligent vehicle development: trustworthy algorithm design (TAD). TAD demonstrates trustworthiness as an ongoing process, not just a measurable outcome from human-technology interactions. It calls to consider autonomous vehicle algorithms as construed through a network of stakeholders, practices, and technologies and, therefore, defines trustworthy algorithm design as a continuous collaborative learning and evolvement process of different disciplines and sectors. Furthermore, the TAD framework suggests that for autonomous vehicle algorithm design to be trustworthy, it must be responsive, interventional, intentional and transdisciplinary. The TAD framework integrates ideas and strategies from different well-known trajectories of research in the field of responsible and human-centred technology development: Human-Centred Algorithm Design (Baumer, 2017), algorithms as culture (Seaver, 2017) and Responsible Innovation (Stilgoe et al., 2013). The thesis contributes to this field by empirically investigating how this integrated framework helps expand existing understandings of interactional trust in intelligent technologies and include the relevance of participatory processes of trustworthiness and how these processes are nurtured through cross-sector co-learning and design ethnographic materials.
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| 4. |
- Elhamili, Anisa
(author)
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Development of Capillary Electrophoresis Methods Coupled to Mass Spectrometry for Biomedical and Pharmaceutical Analysis
- 2011
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Doctoral thesis (other academic/artistic)abstract
- The analysis of large intact proteins and complex biological samples containing drug molecules is a common complicated task for many scientists. However, due to the importance of these molecules, there is a growing interest in pharmaceutical and medicinal research to develop rapid, highly sensitive and efficient analytical techniques. The advantages of capillary electrophoresis (CE) in combination with mass spectrometry (MS) provide a powerful analytical tool. However, further improvement and development of these techniques are required to extend their utility and to meet the challenges of selected analytes. Thus, the scope of this thesis deals with the development of novel analytical methods to achieve efficient and high performance analysis of peptides, intact proteins, digests of complex samples and basic pharmaceutical drug compounds in biological matrices. Implementation of CE for routine analysis of proteins and complex samples is constrained by the partial adsorption to the capillary wall. Consequently, the use of surface modified capillaries is required to control the surface properties and prevent analyte adsorption. In this thesis, analyte adsorption was successfully prevented using tailored covalent cationic (M7C4I) and electrostatic cationic (PVPy-Me) coatings. Rapid and efficient separations of peptides, proteins and digests of complex samples such as cerebrospinal fluids were obtained with these coatings. The M7C4I coating showed a distinct ability to handle large intact proteins with a molecular size of over 0.5 MDa. The highest peak efficiencies and surprisingly high peak stacking effects were obtained by adding salts to the protein samples. The effect of salt additives on peak efficiencies of intact proteins was further demonstrated and compared using different surface modified capillaries. Additionally, rapid CE-ESI-MS quantification of pharmaceutical drug molecules in human plasma was performed after a SCX-SPE sample preparation method using the M7C4I coating. In conclusion, the results presented in this thesis show the strong potential of CE in combination with MS using electrospray ionization (ESI) for the analysis of peptides and large intact proteins and the applicability for clinical monitoring of the levels of pharmaceutical drug molecules in human plasma with high sensitivity and efficiency.
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| 5. |
- Lindberg, Susanne, 1987-
(author)
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Ethics of User Involvement in Sensitive Design Situations
- 2018
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Doctoral thesis (other academic/artistic)abstract
- While this era of digital technology brings great possibilities for improving the lives of many people with digital healthcare services, the design of these services in turn present challenges that are ethical in nature. Participatory Design (PD) values user involvement in design from a democratic, empowerment and ethical perspective. However, the design of digital healthcare services constitutes sensitive design situations, that is, situations that have the potential to negatively impact the participants. As a consequence, participation in these design situations involves risks, causing ethical dilemmas. The ethical dilemmas that designers face in sensitive design situations are situated, dynamic, diverse, unpredictable, and occur in-action. Yet, it is a complex field with little in situ support for designers who intend to involve users in sensitive design situations, and high complexity and risk increase the need to understand ethics in these situations. Consequently, this thesis intends to answer the question: How can users be involved in sensitive design situations?The research question has emerged from the study of two design projects and is addressed through a Design Research (DR) approach. Both projects aimed at designing Digital Peer Support (DPS); one designs DPS for children between 8-12 cured from cancer, and the other designs DPS for people diagnosed with schizophrenia. The DR approach enables the study of de facto design situations in the two design projects. The thesis consists of a collection of five papers and a cover paper.The results show that, in sensitive design situations it can be challenging to uphold the fundamental ethical commitments of PD: that participation is a democratic right, the user is the expert, design should enhance, and design is situated. Based on the empirical study, I propose four principles for ethics in sensitive design situations that aim to support the upholding of these ethical commitments: (I) the principle of enhancement; (II) the principle of acknowledgement; (III) the principle of advocacy; and (IV) the principle of accommodation.The research contributes to the discourse on ethics in PD by expanding the understanding of ethical values of user involvement. Ethical guidelines must be dynamic and responsive, and participation should be carried out using methods for continuous critical reflection. The research contributes to practice by providing practical guidance for those who intend to involve users in sensitive design situations, ethical review boards who review PD, and for training of future PD researchers.
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| 6. |
- Gonçalves, Dulce, 1968-
(author)
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Organizational Agility and Digital Innovation Capability : The Case of Automotive Startups
- 2022
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Doctoral thesis (other academic/artistic)abstract
- An increasingly digital world requires organizations to act more agilely, to succeed in responding quickly when changes or new opportunities arise. The increased digitalization creates a need for organizations to develop an ability to quickly deliver digital innovation, with quality to meet changing customer needs over time. This need for agility to support innovation has aroused interest among information systems researchers in recent years. Two different research streams on agility exist, with the following perspectives: organizational agility concerning IT strategies and operations for organizational cost efficiency; and agile methods in software development, to achieve continuous rapid delivery of digital solutions that meet customer needs. The current information systems literature on organizational agility covers only the first-mentioned perspective, leaving a knowledge gap. To fill the gap we must have a broader understanding of how organizational agility relates to achieving high-paced digital innovation capability.This thesis intends to broaden our understanding of how organizational agility impacts digital innovation by reporting my studies of startups in the automotive industry. The reasons for studying automotive startups are twofold: (a) media reports have indicated that startups generally seem be successful at high-paced digital innovation despite limited means, and (b) some of these startups have begun to challenge automotive incumbents. This aroused an interest in better understanding how startups achieve this ability, and whether there are any lessons that are transferable to incumbents. Therefore this thesis contributes to a broader perspective of organizational agility by addressing the research question: How do startups use organizational agility to drive digital innovation?Results from the research show that not all startups possess equal abilities in terms of organizational agility for digital innovation. This research has identified nine organizational agility capabilities, which form four organizational agility readiness patterns impacting digital innovation.This research provides a theoretical contribution to organizational agility by showing that an amalgamation of two research streams in the information systems literature is needed to achieve a more holistic approach. This approach is needed as the role of IT has changed, from a primary focus on supporting organizational efficiency and cost savings to today, when IT plays a vital strategic role through digital innovation. The two information systems research streams concerning agility are: a) IT strategies and operations supporting organizational efficiency, and b) software development as an innovation outcome. Currently, the information systems research on organizational agility primarily covers only how agility relates to the IT role of supporting efficiency. This research argues that a broader perspective on organizational agility is needed, to understand better which organizational agility capabilities impact digital innovation and how they impact it.The empirical contribution is the identification of nine organizational agility capabilities, which form four organizational agility patterns that affect digital innovation capability to varying degrees. It is crucial that organizations be knowledgable about these nine organizational agility capabilities, since how they manage them will result in different digital innovation capabilities. The contribution to practice is the conceptual framework of four agility readiness patterns for digital innovation. These can be used to evaluate organizations' current digital innovation capability, and guide them as to which capabilities they may need to improve if they want to develop another level of digital innovation capability. The nine organizational agility capabilities identified in this research represent a minimum set that an organization needs to manage knowledgeably, in order to become an agile enterprise for digital innovation.
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| 7. |
- Levin, Mikael, 1981-
(author)
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Att elda för kråkorna? : hushållens energianvändning inom bostadssektorn i Sverige 1913-2008
- 2014
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Doctoral thesis (other academic/artistic)abstract
- This thesis investigates the development of the long-term energy consumption in the Swedish households by estimating the sector’s total energy use and moreover, by examining how structural, institutional and economic factors have affected the demand for energy in the residential sector during the period 1913-2008. The investigated period covers a transition from traditional fuels, such as firewood, to fossil fuels and finally renewable energy. Previous quantitative research in the field of energy history has mainly focused on estimates of the primary energy supply, and further, this research has primarily been supply-oriented and has therefore focused the production of energy and the supporting infrastructure. Overall, there is currently a lack of knowledge covering the long-term patterns in Swedish household’s energy consumption, including changes of the household energy mix. Identifying the central mechanisms behind these changes is the central research question in this thesis. Improved understanding of the energy transformation in Swedish households constitutes important knowledge for all actors who address energy and climate policy, not the least are knowledge about the complex factors that have affected the household consumption of fossil fuels, and thereby the household’s carbon dioxide emissions, important.- The aim of this thesis is to contribute to a better under-standing of the households' role in the energy system and how this role has changed during the 1900s until 2008. The thesis uses a structural analytical approach, based on the concepts suggested by foremost Olle Krantz and Lennart Schön, to understand how the household’s energy consumption is linked to structural changes and techno-logical development. Although the structural analytical chronology, as suggested by Schön, primary builds on the industrial sector, the households can be expected to follow a similar pattern of transformation. This since general-purpose energy technologies is central for the pattern of transformation. However, since different sectors face different conditions and different abilities to utilize the energy, it is equally plausible to assume that the households follow a different pattern than other sectors. The response could either have been faster or slower. The thesis concludes that the period covering the years 1913 to 1973 was a catching-up phase. The households lagged behind the industrial sector with respect to the transition to coal, electricity and oil. But in 1973 the households had however a similar energy mix to other sectors. The second conclusion is therefore that the households made a faster transition from oil to electricity and district heating. After 1985 the household’s energy mix took a different path compared to other sectors, which is the third conclusion. After 1985 the household’s oil consumption continued to decline as the consumption of district heating was increasing. The households were also more prone to increase their consumption of bio-fuels during the 1990s.
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| 8. |
- Arvidsson, Björn, 1974-
(author)
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Quantitative Bioanalysis : Liquid separations coupled to targeted mass spectrometric measurements of bioactive compounds
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Performing quantitative analysis of targeted bioactive compounds in biological samples, such as blood plasma, cerebrospinal fluid or extracts from pig liver, put high demands on the ruggedness of the method acquiring the results. In addition to the complexity of the sample matrix, the bioactive compounds targeted for analysis usually have low levels of natural abundance, further increasing the demand on the analytical method sensitivity. Furthermore, quantitation of analytes at trace levels in the presence of large amounts of interfering species in biofluids must aim for repeatable precision, high accuracy ensuring the closeness to the true values, a linear response spanning over several orders of magnitude and low limits of quantitation to be valid for monitoring disease states in clinical analysis.An analytical method most commonly follow a certain order of events, called the analytical chain, which includes; experimental planning, sampling, sample pre-treatment, separation of species, detection, evaluation, interpretation and validation, all equally important for the outcome of the results.In this thesis, the scope has been to create novel methods, or to refine already existing methods, in order to achieve even better performances of the different events in the analytical chain.One of the aspects has been to sample and enrich analytes in vivo by the use of solid supported microdialysis, giving the advantage of almost real-time monitoring of analyte levels within a living host with targeted selectivity due to the analyte affinity for solid particles. Another aspect to selectively clean and enrich analytes in a complex matrix has been developed and automated on-line by the use of a column-switching technique before the analytical separation. By using several steps of extraction and separation coupled on-line to selected detection by the use of a triple quadrupole mass spectrometer facilitates great selectivity of species. The mass spectrometer also gives the ability to distinguish between isotopically labelled analogues coeluting with the analytes yielding the necessary accuracy for quantitative evaluation.Both development of analytical methods and clinical applications has been performed, as well as improvements of existing techniques, all to improve the quantitation of trace levels of targeted analytes in biofluids.
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| 9. |
- Lilljegren, Josef, 1984-
(author)
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Networks that organised competition : corporate resource sharing between Swedish property underwriters 1875-1950
- 2019
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Doctoral thesis (other academic/artistic)abstract
- This thesis investigates the corporate networks of Swedish property underwriters 1875-1950. During this period, networks of increasing intensity was an essential part in the organisation of the Swedish property insurance market. Corporate resource sharing allowed underwriters to accommodate the ever-changing industrialised demand for property insurance. Interlocking directorates, ownership ties and membership in collaborative organisations were the vessels of this corporate resource sharing.This study proposes a network perspective on the organisation of competition and collaboration. It finds that networks lowered firms’ cost-threshold for underwriting diversification, causing wellconnected firms to expand into new markets more easily. An essential resource to underwriters was information, and information exchange motivated several interfirm rapprochements. The driving forces for the organisational shift towards increased networking were, however, complex, and included both socioeconomic and strategic factors.Through networks of mutual resource sharing, the consolidation that appears in the industry after 1950 was preceded by a long historical process in which firms who would later merge developed measurably clustered network structures as early as in the 1910s. In the 1920s the networks already contributed to a high market concentration. Networks thereby conditioned the underwriting operation of individual firms as well as the structural evolution of the Swedish insurance market as a whole.
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| 10. |
- Padyab, Ali
(author)
-
Exploring Impacts of Secondary Information Use on Individual Privacy
- 2018
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Doctoral thesis (other academic/artistic)abstract
- Information collected from individuals via online social networks and Internet of things devices can be used by institutions and service providers for different business purposes to tailor and customize their services, which is defined as secondary use of information. Although the literature on secondary use is well developed, prior studies have largely focused on direct use of information such as those instances of information use that do not stem from data mining. Advances in data mining and information-processing techniques facilitate discovery of customers’ and users’ behaviors and needs. Research shows that individuals’ behavior can be inferred with high accuracy from their shared information, which may in turn jeopardize privacy. A recent scandal of Cambridge Analytica using about 87 million Facebook profiles to target those users with customized micro-targeted political ads has created public outrage and raised criticisms of secondary use. Given this background, the purpose of this thesis is to explore impacts of organizations’ and service providers’ secondary use of personal information in order to draw conclusions related to how individuals’ attitudes are formed and what role secondary use plays in managing privacy.This research investigates user awareness and attitudes towards potential secondary uses of information. To pursue this, a multi-method qualitative approach using a descriptive questionnaire with 1000 European citizens and a total of 10 focus groups with 43 participants was employed. A qualitative content analysis using both inductive and deductive approaches was conducted to analyze the results. The conceptual framework employed in this thesis was genres of disclosure.The research results suggest that user awareness of the potential for indirect personal information disclosure was relatively low. It was consequently found that participant attitudes toward privacy and disclosure shifted from affective to cognitive when they experienced firsthand the potential inferences that could be made from their own data. Generally, the participant users only considered their direct disclosure of information; through observing potential indirect inferences about their own shared contents and information, however, the participants became more aware of potential infringements on their privacy.The study contributes to information privacy and information systems literature by raising understanding of the impacts of secondary use, in particular its effects on individual privacy management. In addition, this thesis suggests that information privacy is affected differently by direct and indirect uses. Its contribution to information privacy research is to complement previous methodological approaches by suggesting that if users are made aware of indirect inferences that can be made from their content, negative affective responses decrease while cognitive reactions increase through the processing of information related to their disclosure genres. The reason is that indirect use of information inhibits the negotiation of information privacy boundaries and creating unresolved tensions within those boundaries. Cognitive awareness of inferences made to individual information significantly affects the privacy decision-making process. The implication is that there is a need for more dynamic privacy awareness mechanisms that can empower users by providing them with increased awareness of the indirect information they are sharing.
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| 11. |
- Sjödin, Marcus O.D. 1978-
(author)
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Advances for Biomarker Discovery in Neuroproteomics using Mass Spectrometry : From Method Development to Clinical Application
- 2012
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Doctoral thesis (other academic/artistic)abstract
- Proteins offer a prominent group of compounds which may be ubiquitously affected in disease and used as biomarkers for early diagnosis, assessing treatment or drug development. Clinical proteomics aim to screen for protein biomarkers by a comprehensive analysis of all proteins expressed in a biological matrix during a certain pathology. Characterization of thousands of proteins in a complex biological matrix is from an analytical point of view a challenging task. Hence, sophisticated methods that are sensitive, specific and robust in a high-throughput manner are required. Mass spectrometry (MS) is able to perform this to a wide extent is.A prominent source for finding protein biomarkers related to neurological diseases is the central nervous system (CNS) due to close proximity of the pathogenesis. Neuroproteomic analysis of CNS tissue samples is thus likely to reveal novel biomarkers. Cerebrospinal fluid (CSF) bathes the entire CNS and offers a good balance between clinical implementation and usefulness. Both matrices put further requirements on the methodology due to a high dynamic range, low protein concentration and limited sample amount.The central objective of this thesis was to develop, assess and utilize analytical methods to be used in combination with MS to enable protein biomarker discovery in the CNS. The use of hexapeptide ligand libraries was exemplified on CSF from patients with traumatic brain injury and demonstrated the ability to compress the dynamic range to enable protein profiling in the order of mg/mL to pg/mL. Further, a method based on cloud-point extraction was developed for simultaneous enrichment and fractionation of hydrophobic/hydrophilic proteins in brain tissue. Comparison between label and label-free MS based strategies were carried out, mimicking the true conditions with a few differentially expressed proteins and a bulk of proteins occurring in unchanged ratio. Finally, a clinical application was carried out to explore the molecular mechanism underlying the analgesic effect of spinal cord stimulation (SCS) in patients with neuropathic pain. The CSF concentration of Lynx1 was found to increase upon SCS. Lynx1, acting as a specific modulator of the cholinergic system in the CNS, may act as a potential important molecular explanation of SCS-induced analgesia.
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| 12. |
- Wetterhall, Magnus, 1973-
(author)
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Electrifying the Molecules of Life : Peptide and Protein Analysis by Capillary Electrophoresis Coupled to Electrospray Ionization Mass Spectrometry
- 2004
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Doctoral thesis (other academic/artistic)abstract
- This thesis describes the current status and novel aspects of the analysis of the molecules of life, i.e. peptides and proteins, using capillary electrophoresis (CE) coupled to mass spectrometry (MS) via (sheathless) electrospray ionization (ESI). Early reports of sheathless CE-ESI-MS were plagued by limited lifetimes of the electrospray emitter. In this thesis, two new approaches, the Black Dust and the Black Jack methods, utilizing polymer-embedded graphite instead of noble metals are presented. These emitters have shown improved long-term stability and proven excellent for sheathless electrospray operation. Failure of an emitter is often caused by electrochemical reactions occurring at the emitter-liquid interface. The electrochemical properties of the graphite coated emitters were therefore evaluated by classical electrochemical methods, such as cyclic voltammetry and chronoamperometry. The graphite coated emitters showed excellent electrochemical stability and properties compared to noble metal and polymer configurations. Analyte-wall interactions have long been known to cause problems in the CE analysis of biomolecules. This can be circumvented by internal modification of the capillary walls. Additionally, it is of outermost importance to have a stable and sufficiently high electroosmotic flow (EOF) to sustain the electrospray, when using a sheathless approach. New monomer and polymer coatings are presented for rapid and high-efficient CE-ESI-MS separations of peptides and proteins. Furthermore, the use of CE-ESI coupled to Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) shows great potential for rapid proteomic probing of human cerebrospinal fluid. The results are comparable with more established techniques, such as liquid chromatography and two-dimensional gel electrophoresis coupled to MS. However, the CE-ESI-FTICRMS analysis has significantly lower sample consumption and faster analysis time compared to the other techniques. The applications and use of CE-ESI-MS is expected to have a bright future with continued growth as current trends of multidimensional hyphenation and microfabricated devices are further developed and explored.
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