الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Sample preparation is typically the most tedious part in bioanalysis. However, it is indispensable to enrich analytes of interest and/or to remove the interferences from complex matrices thus there are intense efforts to automate and integrate sample preparation with the detection step. This thesis presents the first implementation of an electrokinetic technique within a syringe exploiting the embedded stainless steel syringe needle and plunger as electrodes and the syringe barrel as a separation channel. The preparation of complex biological samples in a syringe, the most common liquid handling device, allows for sample dilution, electrokinetic focusing of the targeted compounds and/or removing the interfering molecules, and finally the infusion to the analyzer, mainly electrospray ionization-mass spectrometry (ESI-MS) using a single platform. Moreover, minimal use of organic solvents was offered by the electrokinetic technique. The first Chapter provides an insight into the current sample preparation strategies directly coupled with ESI-MS for biofluids analysis while the experimental Chapters show the development of the in-syringe extraction-ESI-MS systems. The first in-syringe system was dedicated to the isoelectric focusing (IEF) of amphoteric compounds such as proteins and amino acids at the formed neutralization reaction boundary (NRB). The IEF syringe-ESI-MS system was applied for the analysis of histidine in spiked urine samples as relevant for the diagnosis of histidinemia. Furthermore, electrokinetic extraction (EkE) syringes were presented for the on-line electrokinetic removal of serum proteins to allow for ESI-MS detection with minimal ion suppression. Two systems were investigated targeting weakly acidic compounds and weakly basic compounds (pressurized bubble-free system). The proposed concept was demonstrated by the determination of pharmaceuticals from human serum within a few minutes. Additionally, an automated platform is proposed and designed.