Disulfide bonds play important roles in establishing and stabilizing three-dimensional protein structure, and mass spectrometry (MS) has become the primary detection method to decipher their biological and pathological roles. Several experimental methods before or after MS detection have been developed to aid in disulfide bond assignment, such as tandem MS followed by database searching or modification of the disulfide bond via chemical reduction or oxidation. Despite these technological advancements, the detection and proper assignment of disulfide bonds have remained experimentally difficult. Therefore, we have developed an alternative method for disulfide bond elucidation using capillary electrophoresis-mass spectrometry (CE-MS) combined with an on-target performic acid oxidation method for matrix assisted laser desorption/ionization (MALDI) deposited samples. An information rich CE-MS method that results in distinct charge-state trends observed in two-dimensional plots of log(mu eff) versus log (MW) was developed to enhance the confidence of peptide and protein identifications. The charge-state trends provide information about the number of basic amino acid residues present within each peptide. This information can be used to develop methods to screen for posttranslationally modified peptides (e.g., phosphorylation, disulfide bonds, etc.). In the case of disulfide bonds, the highly charged peptides (i.e., 3, 4 or greater charge states) have a high probability of being disulfide-linked peptides, owing to charge contribution of both peptides forming the disulfide bridged peptide. However, intra-linked disulfide bridged peptides can also be present at lower charge states. Therefore, a chemically selective method to rapidly locate disulfide-linked peptides that have been separated by CE-MS must be developed. An on-target performic acid oxidation method was developed to provide the chemical selectivity towards disulfide bonds, i.e., converting the cystine bond to form two peptides modified with a cysteic acid (SO3H) side chain. The on-target oxidation method offers (i) no post-oxidation sample cleanup, (ii) improved throughput over solution-phase oxidation methods, and (iii) easily adapted to CE separations coupled offline with MALDI-MS. The evaluation of the on-target oxidation experimental parameters, the fragmentation behavior of cysteic acid-containing peptides and an alternative method for disulfide bond elucidation, using CE-MS combined with the ontarget oxidation method, are discussed within.

Abstract This thesis examines three different areas of water treatment technology: the application of organic peracids in wastewater treatment; the removal of organic residues from boiler make-up water; and the use of geopolymers as sorbents. The main advantages of peracids as alternative wastewater disinfectants are their effective antimicrobial properties and high oxidation power, as well the absence of harmful disinfection by-products after their use. Performic, peracetic and perpropionic acids were compared in laboratory-scale disinfection, oxidation and corrosion experiments. From the techno-economical point of view, performic acid proved to be the most effective disinfectant against E. coli and fecal enterococci. However, in the bisphenol-A oxidation experiments, no advantages compared to hydrogen peroxide use were observed. It was also determined that corrosion rates on stainless steel 316L were negligible, while carbon steel seemed unsuitable in terms of corrosion for use with peracids even in low concentrations. Organic compounds in the boiler plant water-steam cycle thermally decompose and form potentially corrosive species. Activated carbon filtration was confirmed to be a suitable method for the removal of organic residue from deionized boiler make-up water. No significant differences in terms of treatment efficiency between commercial activated carbons were observed. However, acid washing as a pre-treatment reduced the leaching of impurities from new carbon beds. Nevertheless, a mixed-bed ion exchanger was required to remove leached impurities, such as silica and sodium. Geopolymers, or amorphous analogues of zeolites, can be used as sorbents in the treatment of wastewater. Metakaolin and blast-furnace-slag geopolymers showed positive potential in the treatment of landfill leachate (NH4+ ) and mine effluent (Ni, As, Sb). / Tiivistelmä Tämä väitöskirja käsittelee kolmea erillistä vedenkäsittelyteknologian osa-aluetta: orgaanisten perhappojen käyttöä jäteveden käsittelyssä, orgaanisten jäämien poistoa suolavapaasta kattilalaitoksen lisävedestä ja geopolymeerien sovelluksia vedenkäsittelysorbentteina. Orgaanisten perhappojen pääasialliset edut verrattuna kilpaileviin tekniikoihin ovat hyvä desinfiointiteho, korkea hapetuspotentiaali ja desinfioinnin sivutuotteiden muodostumattomuus. Permuurahais-, peretikka- ja perpropaanihapon vertailu osoitti permuurahaishapon olevan kemikaaleista tehokkain E. coli - ja enterokokkibakteerien inaktivoinnissa kustannus- ja teknisistä näkökulmista. Hapetuksessa, jossa käytettiin bisfenoli-A:ta malliaineena, ei kuitenkaan havaittu etua verrattuna edullisempaan vetyperoksidiin. Ruostumattoman teräksen (316L) pinnalla ei havaittu merkittävää korroosiota, kun taas hiiliteräs ei sovellu käytettäväksi perhappojen kanssa. Orgaaniset jäämät kattilalaitoksen vesi-höyrykierrossa hajoavat termisesti pienen moolimassan hapoiksi ja aiheuttavat korroosioriskin. Aktiivihiilisuodatuksen todettiin olevan soveltuva menetelmä orgaanisten jäämien poistoon lisävedestä. Aktiivihiililaatujen välillä ei havaittu merkittäviä eroja, mutta happopesu aktiivihiilen esikäsittelynä vähensi hiilestä liukenevien epäpuhtauksien määrää. Geopolymeerit ovat zeoliittien amorfisia analogeja ja niiden ioninvaihtokykyä voidaan hyödyntää vedenkäsittelysovelluksissa. Metakaoliini- ja masuunikuonapohjaisten geopolymeerien todettiin olevan lupaavia materiaaleja malliliuosten, kaatopaikan suotoveden ja kaivoksen purkuveden käsittelyssä poistettaessa ammoniumia, nikkeliä, arseenia ja antimonia.