To understand the glass electrode needs knowledge from more than one level. The construction ofthe glass electrode is one part, an other is the composition and structure of glass. The Nernstequation have an important role, but also the sources of errors in the analysis and the calibration ofthe glass electrode. Focus for this article is how the glass electrode really works and how Gibbs freeenergy made the potential dependent of the concentration of H+and gives the logarithm to thefunction. Nikolskii's ion exchange theory starts to explain the question about how the potentialcreates and Baucke's dissociation mechanism made it more explicit. The big different in theequations from the both theories respectively is the meaning of the constants, but for practical useof the glass electrode in analysis it is not important when the value of the constant is given bycalibration. This is not an excuse for that fact that the dissociation mechanism is more completethan the ion exchange theory in the understanding of the glass electrode. / För att förstå hur glaselektroden fungerar krävs kunskap från mer än ett plan. Glaselektrodenskonstruktion är en del, glasets kemiska struktur en annan. Nernst ekvationen spelar en viktig roll,men även felkällorna i de analyser som görs med glaselektrod, (vanligtvis pH-mätning), samtkalibreringen av glaselektroden. I den här uppsatsen ligger fokus på hur glaselektroden faktisktfungerar och hur Gibbs fria energi gör potentialen beroende av koncentrationen vätejoner och tillförlogaritmen i funktionen för glaselektroden. Nikolskii's ion exchange theory påbörjar förklaringen avpotentialens uppkomst och Baucke's dissociation mechanism gör den tydligare. Skillnaden mellanrespektive teori och dess matematiska funktion är konstantens innebörd och betydelse, men för denpraktiska användningen av glaselektroden till analyser är detta av mindre vikt då konstantens värdefås genom kalibrering. Detta är dock ingen ursäkt för det faktum att the dissociation mechanism geren mer fullständig förklaring och ökad förståelse för hur glaselektroden fungerar än the ionexchange theory.

Oligoperoxides, H[OO(CH3)2C]nOOH, are formed as side products in the synthesis of the primary high explosive triacetone triperoxide (TATP). Previous tandem mass spectrometry (MSn ) experiments using a quadrupole ion trap reported that the openchained oligoperoxide adducts of ammonium or sodium resulted in different product ions in the mass spectra. Dissociation mechanisms were previously proposed based on MSn experiments, where n > 2; however, a dissociation pathway achieved by an MSn experiment, where n > 2, may not necessarily be the same pathway achieved in an MS2 experiment. For this dissertation research, the collision induced dissociation pathways were investigated for the open-chained oligoperoxides in MS2 experiments utilizing a quadrupole ion trap. Tandem mass spectral experiments were performed for the openchained oligoperoxides ranging from the trimer to the octamer (n=3-8), including both ammonium and sodium adducts. The dissociation pathways were proposed as a result of two-dimensional correlation spectroscopy applied to the mass spectral data, which was referred to as two-dimensional correlation mass spectrometry (2D-CMS). The 2DCMS method was first validated by analysis of simple and more complex kinetic models followed by simple and more complex molecules. To further aid in the elucidation of the dissociation mechanisms, computational chemistry was performed for the optimization of stable precursor and product ion structures and calculations of their relative energies and adduct dissociation energies.

The diffusible soluble oligomeric amyloid β-peptide (Aβ) has been identified as a toxic agent in Alzheimer’s disease that can cause synaptic dysfunction and memory loss, indicating its role as potential therapeutic targets for AD treatment. Recently an oligomer-specific sandwich biotin-avidin interaction based assay identified the Aβ oligomer dissociation potency of a series of dihydroxybenzoic acid (DHBA) isomers. Because the sandwich assay is an ensemble method providing limited size information, fluorescence correlation spectroscopy (FCS) was employed to provide single molecule resolution of the disassembly mechanism. Using FCS coupled with atomic force microscopy, we investigated the size distribution of fluorescein labeled synthetic Aβ oligomers at physiological concentrations, and monitored in real time the change of size and mole fraction of oligomers in the presence of dissociating agents or conditions. The higher-order dissociation process caused by DHBA isomers produced no transient oligomeric intermediates, a desirable feature for an anti-oligomer therapeutic. Urea and guanidine hydrochloride, in contrast, produced a linear dissociation with a progressive decrease of size and mole fraction of oligomers. FCS allows the facile distinction of small molecule Aβ oligomer dissociators that do not produce stable potentially toxic oligomeric Aβ intermediates.