Elsa Lundanes

• Levernæs, Maren Christin Stillesby; Brandtzaeg, Ole Kristian; Amundsen, Sunniva Furre; Reubsaet, Leon; Lundanes, Elsa; Halvorsen, Trine Grønhaug & Wilson, Steven Ray Haakon (2018). Selective Fishing for Peptides with Antibody Immobilized Acrylate Monoliths, Coupled Online with NanoLC-MS. Analytical Chemistry.  ISSN 0003-2700.  90, s 13860 . doi: 10.1021/acs.analchem.8b00935
• Poothong, Somrutai; Papadopoulou, Eleni Zoumpoulia; Lundanes, Elsa; Padilla Sanchez, Juan Antonio; Thomsen, Cathrine & Haug, Line Småstuen (2018). Dried blood spots for reliable biomonitoring of poly- and perfluoroalkylsubstances (PFASs). Science of the Total Environment.  ISSN 0048-9697.  655, s 1420- 1426 . doi: 10.1016/j.scitotenv.2018.11.214
• Skottvoll, Frøydis Sved; Berg, Henriette Engen; Bjørseth, Kamilla; Lund, Kaja; Roos, Norbert; Bekhradnia, Sara; Thiede, Bernd; Sandberg, Cecilie; Vik-Mo, Einar O.; Røberg-Larsen, Hanne; Nyström, Bo; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Ultracentrifugation versus kit exosome isolation: nanoLC-MS and other tools reveal similar performance biomarkers, but also contaminations. Future science OA.  ISSN 2056-5623.  5(1) . doi: 10.4155/fsoa-2018-0088
• Berg, Henriette Sjånes; Sæterdal, Kristina Erikstad; Smetop, Tone; Rozenvalds, Rūdolfs; Brandtzaeg, Ole Kristian; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Self-packed core shell nano liquid chromatography columns and silica-based monolithic trap columns for targeted proteomics. Journal of Chromatography A.  ISSN 0021-9673.  1498, s 111- 119 . doi: 10.1016/j.chroma.2017.03.043
• Brandtzaeg, Ole Kristian; Røen, Bent Tore; Enger, Siri; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Multichannel open tubular enzyme reactor online coupled with mass spectrometry for detecting ricin. Analytical Chemistry.  ISSN 0003-2700.  89(17), s 8667- 8673 . doi: 10.1021/acs.analchem.7b02590
• Comninos, Alexander N; Wall, Matthew B; Demetriou, Lysia; Shah, Amar J; Clarke, Sophie A; Narayanaswamy, Shakunthala; Nesbitt, Alexander; Izzi-Engbeaya, Chioma; Prague, Julia K; Abbara, Ali; Ratnasabapathy, Risheka; Salem, Victoria; Nijher, Gurjinder M; Jayasena, Channa N; Tanner, Mark; Bassett, Paul; Mehta, Amrish; Rabiner, Eugenii A; Hönigsperger, Christoph; da Silva, Meire Ribeiro; Brandtzaeg, Ole Kristian; Lundanes, Elsa; Wilson, Steven Ray Haakon; Brown, Rachel C; Thomas, Sarah A; Bloom, Stephen R & Dhillo, Waljit S (2017). Kisspeptin modulates sexual and emotional brain processing in humans. Journal of Clinical Investigation.  ISSN 0021-9738.  127(2), s 709- 719 . doi: 10.1172/JCI89519
• da Silva, Meire Ribeiro; Brandtzaeg, Ole Kristian; Vehus, Tore; Lancas, Fernando Mauro; Wilson, Steven Ray Haakon & Lundanes, Elsa (2017). An automated and self-cleaning nano liquid chromatography mass spectrometry platform featuring an open tubular multi-hole crystal fiber solid phase extraction column and an open tubular separation column. Journal of Chromatography A.  ISSN 0021-9673.  1518, s 104- 110 . doi: 10.1016/j.chroma.2017.08.071
• Gregus, Michael; Røberg-Larsen, Hanne; Lundanes, Elsa; Foret, Frantisek; Kubán, Petr & Wilson, Steven Ray Haakon (2017). Non-aqueous capillary electrophoretic separation of cholesterol and 25-hydroxycholesterol after derivatization with Girard P reagent. Chemistry and Physics of Lipids.  ISSN 0009-3084.  207, s 87- 91 . doi: 10.1016/j.chemphyslip.2017.05.014
• Gundersen, Cathrine Brecke; Zhu, Liang; Lindahl, Sofia; Wang, Shiyu; Wilson, Steven Ray Haakon & Lundanes, Elsa (2017). LC-MS/MS Method for Simultaneous Determination of Monoethanol- and Dimethylnitramine in Aqueous Soil Extracts. Chromatographia.  ISSN 0009-5893.  80(9), s 1475- 1481 . doi: 10.1007/s10337-017-3355-6
• Poothong, Somrutai; Lundanes, Elsa; Thomsen, Cathrine & Haug, Line Småstuen (2017). High throughput online solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry method for polyfluoroalkyl phosphate esters, perfluoroalkyl phosphonates, and other perfluoroalkyl substances in human serum, plasma, and whole blood. Analytica Chimica Acta.  ISSN 0003-2670.  957, s 10- 19 . doi: 10.1016/j.aca.2016.12.043 Full text in Research Archive.
• Pugajeva, Iveta; Rusko, Janis; Perkons, Ingus; Lundanes, Elsa & Bartkevics, Vadims (2017). Determination of pharmaceutical residues in wastewater using high performance liquid chromatography coupled to quadrupole-Orbitrap mass spectrometry. Journal of Pharmaceutical and Biomedical Analysis.  ISSN 0731-7085.  133, s 64- 74 . doi: 10.1016/j.jpba.2016.11.008
• Reinholds, I; Pugajeva, Iveta; Zacs, Dz; Lundanes, Elsa; Rusko, Janis; Perkons, Ingus & Bartkevics, Vadims (2017). Determination of acidic non-steroidal anti-inflammatory drugs in aquatic samples by liquid chromatography-triple quadrupole mass spectrometry combined with carbon nanotubes-based solid-phase extraction. Environmental Monitoring & Assessment.  ISSN 0167-6369.  189(11) . doi: 10.1007/s10661-017-6304-9
• Røberg-Larsen, Hanne; Abele, Silvija; Demir, Deniz; Dzabijeva, Diana; Amundsen, Sunniva Furre; Wilson, Steven Ray Haakon; Bartkevics, Vadims & Lundanes, Elsa (2017). Rugged Large Volume Injection for Sensitive Capillary LC-MS Environmental Monitoring. Frontiers in Chemistry.  ISSN 2296-2646.  AUG(2017) . doi: 10.3389/fchem.2017.00062
• Røberg-Larsen, Hanne; Lund, Kaja; Sæterdal, Kristina Erikstad; Solheim, Stian; Vehus, Tore; Hoen, Nina; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Mass spectrometric detection of 27-hydroxycholesterol in breast cancer exosomes. Journal of Steroid Biochemistry and Molecular Biology.  ISSN 0960-0760.  169, s 22- 28 . doi: 10.1016/j.jsbmb.2016.02.006
• Sandvik, Trude Althammer; Husa, Asgeir; Buchmann, Marie & Lundanes, Elsa (2017). Routine supercritical fluid chromatography tandem mass spectrometry method for determination of vitamin K1 extracted from serum with a 96-well solid phase extraction method. The Journal of Applied Laboratory Medicine.  ISSN 2374-9679.  1, s 637- 648
• Skjærvø, Øystein; Brandtzaeg, Ole Kristian; Lausund, Kristian Blindheim; Pabst, Oliver; Martinsen, Ørjan Grøttem; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Exploring bioimpendance instrumentation for the characterization of open tubular liquid chromatography columns. Journal of Chromatography A.  ISSN 0021-9673.  1534, s 195- 200 . doi: 10.1016/j.chroma.2017.12.060
• Vehus, Tore; Waaler, Jo; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Combining HIC, SEC, and IEX with Fluorescence Polarization for Drug Target Discovery. LC GC North America.  ISSN 1527-5949.  30(5), s 232- 239
• Bergh, Marianne Skov-Skov; Bogen, Inger Lise; Lundanes, Elsa & Øiestad, Åse Marit Leere (2016). Validated methods for determination of neurotransmitters and metabolites in rodent brain tissue and extracellular fluid by reversed phase UHPLC-MS/MS. Journal of chromatography. B.  ISSN 1570-0232.  1028, s 120- 129 . doi: 10.1016/j.jchromb.2016.06.011
• Brandtzaeg, Ole Kristian; Johnsen, Elin Follaug; Røberg-Larsen, Hanne; Seip, Knut Fredrik; MacLean, Evan L.; Gesquiere, Laurence R.; Leknes, Siri; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Proteomics tools reveal startlingly high amounts of oxytocin in plasma and serum. Scientific Reports.  ISSN 2045-2322.  6:31693 . doi: 10.1038/srep31693 Full text in Research Archive.
• Doowod, Rua Kareem; Adusumalli, Ravi; Tykesson, Emil; Johnsen, Elin Follaug; Lundanes, Elsa; Prydz, Kristian & Wilson, Steven Ray Haakon (2016). Determination of 3′-phosphoadenosine-5′-phosphosulfate in cells and Golgi fractions using hydrophilic interaction liquid chromatography–mass spectrometry. Journal of Chromatography A.  ISSN 0021-9673. . doi: 10.1016/j.chroma.2016.10.001
• Johnsen, Elin Follaug; Brandtzaeg, Ole Kristian; Vehus, Tore; Røberg-Larsen, Hanne; Bogoeva, Vanya; Ademi, Ornela; Hildahl, Jon Paul; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). A critical evaluation of Amicon Ultra centrifugal filters for separating proteins, drugs and nanoparticles in biosamples. Journal of Pharmaceutical and Biomedical Analysis.  ISSN 0731-7085.  120, s 106- 111 . doi: 10.1016/j.jpba.2015.12.010
• Vehus, Tore; Røberg-Larsen, Hanne; Waaler, Jo; Aslaksen, Sigrid; Krauss, Stefan; Wilson, Steven Ray Haakon & Lundanes, Elsa (2016). Versatile, sensitive liquid chromatography mass spectrometry–Implementation of 10 μm OT columns suitable for small molecules, peptides and proteins. Scientific Reports.  ISSN 2045-2322.  6 . doi: 10.1038/srep37507 Full text in Research Archive.
• Vehus, Tore; Sæterdal, Kristina Erikstad; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Comparison of commercial nanoliquid chromatography columns for fast, targeted mass spectrometry-based proteomics. Future science OA.  ISSN 2056-5623.  2(2) . doi: 10.4155/fsoa-2016-0014
• Johnsen, Elin Follaug; Leknes, Siri; Wilson, Steven Ray Haakon & Lundanes, Elsa (2015). Liquid chromatography-mass spectrometry platform for both small neurotransmitters and neuropeptides in blood, with automatic and robust solid phase extraction. Scientific Reports.  ISSN 2045-2322.  5 . doi: 10.1038/srep09308 Full text in Research Archive.
• Røberg-Larsen, Hanne; Vesterdal, Caroline; Wilson, Steven Ray Haakon & Lundanes, Elsa (2015). Underivatized oxysterols and nanoLC-ESI-MS: A mismatch. Steroids.  ISSN 0039-128X.  99, s 125- 130 . doi: 10.1016/j.steroids.2015.01.023
• Wilson, Steven Ray Haakon; Vehus, Tore; Berg, Henriette Sjånes & Lundanes, Elsa (2015). Nano-LC in proteomics: Recent advances and approaches. Bioanalysis.  ISSN 1757-6180.  7(14), s 1799- 1815 . doi: 10.4155/bio.15.92
• Hustoft, Hanne Kolsrud; Vehus, Tore; Brandtzæg, Ole Kristian Merkesvik; Krauss, Stefan; Greibrokk, Tyge; Wilson, Steven Ray Haakon & Lundanes, Elsa (2014). Open tubular lab-on-column/mass spectrometry for targeted proteomics of nanogram sample amounts. PLoS ONE.  ISSN 1932-6203.  9(9) . doi: 10.1371/journal.pone.0106881 Full text in Research Archive.

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• Amundsen, Sunniva Furre; Wilson, Steven Ray Haakon; Berg, Henriette Engen; Røberg-Larsen, Hanne & Lundanes, Elsa (2018). Online entrapment of epitope-containing peptides from integrins using immobilized antibodies.
• Ben Hassine, Esma; Lundanes, Elsa; Wilson, Steven Ray Haakon; Vehus, Tore; Brandtzaeg, Ole Kristian & Berg, Henriette Engen (2018). Capillary poly(styrene-co-octadecene-co-divinylbenzene) monolithic trap columns for bioanalytical analysis. Show summary

  The increasing demand for faster and more efficient separations for biological samples have driven organic polymer-based monolithic columns back into the spotlight. The nature of the monolithic structure allows the use of higher flow rates without increasing the system backpressure. They are also easier to contain inside the column body, opposed to particle packed columns, which are held in place by frits. These are some of the advantages that monolithic columns offer compared to particle packed columns. Poly(styrene-co-octadecene-co-divinylbenzene) (PS-OD-DVB) monolithic columns have been prepared and characterized using the neuropeptide oxytocin, “the love hormone” as test compound. The columns, 50 µm inner diameter x 100 mm in length, were to be used as trap columns in a miniaturized liquid chromatography-mass spectrometry (LC-MS) column switching system for bottom-up proteomics analysis. The monolithic PS-OD-DVB columns were prepared in situ (inside the fused silica capillary), using a polymerization mixture consisting of an initiator (lauroyl peroxide), a crosslinker (divinylbenzene), monomers (styrene and 1-octadecene), a good porogen (N,N-dimethylformamide (DMF)) and a bad porogen (1-decanol). Polymerization time, polymerization temperature, initiator concentration, and monomer to porogen ratios were investigated in order to obtain a monolithic structure with a high surface area and good permeability. The best PS-OD-DVB monolithic column was prepared using a mixture of 1.9% lauroyl peroxide (weight percentage of monomer amount), 14.2% divinylbenzene, 15.2% monomers, 11.9% DMF and 57.5% 1-decanol. The column was polymerized for one hour at 73°C and gave a plate height of 62 µm, a backpressure of 23 bar at a flow rate of 500 nL/min with a mobile phase consisting of 20% B (acetonitrile (ACN), water, formic acid (FA), 80/20/0.1, v/v/v) and 80% A (water with 0.1% (v/v) FA) and a retention time repeatability of 2.6% (relative standard deviation). The repeatability of the columns made by various individuals was satisfactory. However, when preparing twenty-one columns by the same individual, the repeatability revealed to be questionable. Hence, further improvements in the polymerization procedure do seem necessary and might be able to enhance the repeatability of the columns.

• Berg, Henriette Sjånes; Bjørseth, Kamilla; Sæterdal, Kristina Erikstad; Smetop, Tone; Skottvoll, Frøydis Sved; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Evaluation of isolation methods of glioma exosomes for biomarker discovery. Show summary

  Gliomas are the most common form of brain cancer, where the sub-group glioblastoma multiforme (GBM) is the most aggressive and the most common in adults [1]. For diagnostic, prognostic, and treatment monitoring, fast and reliable analytical methods for detection of glioblastoma tumors are essential. Non-invasive monitoring of circulating biomarkers in blood (liquid biopsy) is a desirable possibility [2]. Nano LC-MS can provide the high sensitivity, selectivity and low false positive rate needed for the proteomic analysis of exosomes, which are extracellular vesicles released from the tumor and into the bloodstream. We have optimized the packing of 50 µm capillaries (2.6 µm C18 core-shell particles) with peak capacities comparable to similar commercial nano-LC columns (75 µm ID) for peptide separations of minute samples (e.g. exosomes). These columns have previously been successfully used for the targeted detection of CYP27a (a potential breast cancer biomarker) in the MDA-MB-231 cell line. In the present study, these in-house packed columns have been applied for proteins in exosomes isolated from GBM cell culture medium. The aim of this study was to compare isolation methods of GMB exosomes for biomarker discovery and study proteins related to GBM in exosomes. Ultracentrifugation (“golden standard” in exosome isolation) was compared to a Total Exosome Isolation Reagent from Invitrogen (Thermo Fisher Scientific) regarding sample volume, total protein amount, purity, and the presence of exosome markers and GBM biomarker candidates. References 1. Molina, J.R., Y. Hayashi, C. Stephens, and M.M. Georgescu, Invasive Glioblastoma Cells Acquire Stemness and Increased Akt Activation. Neoplasia. 12 (2010) 453-U37. 2. Best, M.G., N. Sol, S. Zijl, J.C. Reijneveld, P. Wesseling, and T. Wurdinger, Liquid biopsies in patients with diffuse glioma. Acta Neuropathologica. 129 (2015) 849-865.

• Brandtzaeg, Ole Kristian; Levernæs, Maren Christin Stillesby; Halvorsen, Trine Grønhaug; Reubsaet, Leon; Røen, Bent Tore; Vehus, Tore; da Silva, Meire Ribeiro; Røberg-Larsen, Hanne; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Online sample processing systems for targeted nano liquid chromatography mass spectrometry bioanalysis.
• Brandtzaeg, Ole Kristian; Røen, Bent Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Qualitative detection of ricin using a multichannel enzyme reactor coupled online with nano liquid chromatography with mass spectrometry detection.
• Brandtzaeg, Ole Kristian; Wilson, Steven Ray Haakon; Lundanes, Elsa; Reubsaet, Leon; Krauss, Stefan & Martinsen, Ørjan Grøttem (2018). Online sample Preparation Platforms for Targeted Nano Liquid Chromatography Mass Spectrometry Bioanalysis. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1968.
• Gundersen, Cathrine Brecke; Vogt, Rolf David; Lundanes, Elsa; Andersen, Tom & Breedveld, Gijs D. (2018). Environmental Fate and Determination of Nitramines Formed from Amine-based CO2 Capture.
• Gundersen, Cathrine Brecke; Vogt, Rolf David; Lundanes, Elsa; Breedvelt, Gijs & Andersen, Tom (2018). Environmental Fate of Nitramines Formed During Amine Based Post-Combustion CO2 Capture.
• Hassine, Esma Ben; Berg, Henriette Engen; Brandtzaeg, Ole Kristian; Vehus, Tore; Wilson, Steven Ray Haakon & Lundanes, Elsa (2018). Capillary poly(styrene-co-octadecene-co-divinylbenzene) monolithic columns.
• Hvinden, Ingvild Comfort; Rise, Frode; Berg, Henriette Engen; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Approaches to untargeted metabolomics of glioblastoma: NMR and MS.
• Hvinden, Ingvild Comfort; Wilson, Steven Ray Haakon; Rise, Frode; Berg, Henriette Engen & Lundanes, Elsa (2018). Nuclear magnetic resonance spectroscopy based metabolomics discovers biomarkers of glioblastoma drug response. Show summary

  Glioblastoma is the most common and aggressive form of brain cancer. Even with comprehensive treatment regimes, patients face an expected survival of only 15 months. Currently, methods for assessing treatment response are lacking; it is difficult to accurately determine the efficacy of a treatment. The goal of the present study was to contribute to treatment assessment by scouting for metabolic biomarkers occurring in response to exposure to chemotherapeutic agents temozolomide (TMZ) and sepantronium bromide (YM155). Untargeted metabolomics of lysate from cultured glioblastoma cells was carried out with liquid state proton nuclear magnetic resonance (NMR) spectroscopy at resonance frequency 800 MHz. Spectral data were analyzed with two different multivariate statistical methods: principal component analysis (PCA) and partial least squares (PLS) regression. For YM155, two biomarker candidates were found: citric and lactic acid. Citric acid appeared to increase most in samples from cell lines less sensitive to YM155. Lactic acid decreased in all cell lines and was considered a more general biomarker of treatment exposure. TMZ-treated samples were not distinguishable from control samples, most likely due to too short exposure time (24 hours). Analyses with nano hydrophilic interaction liquid chromatography coupled with mass spectrometry (MS) corroborated the findings by NMR spectroscopy and statistical analyses. Both citric acid and lactic acid are biomarker candidates, but a more detailed understanding of their fluctuations in glioblastoma during treatment is needed. Nevertheless, they represent genuine candidates and should be considered for further in vivo magnetic resonance spectroscopy (MRS) studies. In the future, the biomarkers could be monitored with MRS, allowing a more unambiguous and personalized assessment of response to treatment in individual patients.

• Kular, Ramneet Kaur; Wilson, Steven Ray Haakon; Røberg-Larsen, Hanne & Lundanes, Elsa (2018). Towards ultrafast liquid chromatography of 3’-phosphoadenosine-5’-phosphosulfate using a short hydrophilic interaction chromatography column.
• Kular, Ramneet Kaur; Wilson, Steven Ray Haakon; Røberg-Larsen, Hanne & Lundanes, Elsa (2018). Towards ultrafast liquid chromatography of 3’-phosphoadenosine-5’-phosphosulfate using zwitterionic hydrophilic interaction liquid chromatography-mass spectrometry.
• Olsen, Christine; Brandtzaeg, Ole Kristian; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). On-line trapping of proteins with monolith-bound drugs, as a tool in drug target discovery.
• Poothong, Somrutai; Haug, Line Småstuen; Thomsen, Cathrine & Lundanes, Elsa (2018). Poly- and perfluoroalkyl substances (PFASs): from external exposure to human blood. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 2043. Show summary

  This thesis contributed to the field of human exposure to environmental pollutants called poly- and perfluoroalkyl substances (PFASs). Daily intakes of PFASs via ingestion, inhalation, and dermal absorption were estimated and compared to the internal doses. Overall, diet contributed most to the daily intake of PFASs, followed by house dust, indoor air, and dermal absorption, but some variations were observed on an individual basis. Significant associations between concentrations of PFASs measured in serum, and estimated intakes based on direct and indirect (precursor) exposure were observed. Measured serum concentrations and modelled serum concentrations based on external exposure estimates were in the same order of magnitude. The estimated daily intakes of PFASs in this study were lower than the health-based guidance values. Also, in this study, analytical methods have been developed and validated for the determinations of a broad range of PFASs in serum, plasma, whole blood, dried blood spot, and hand wipes. This study underlines the importance of performing studies considering multiple exposure pathways on an individual basis.

• Racz, Beatrix; Wilson, Steven Ray Haakon; Rise, Frode & Lundanes, Elsa (2018). Identification of a major UV absorbing compound in goose aqueous humour. Show summary

  About 5% of solar radiation comes from the ultraviolet (UV) region. It carries high energy and can do serious damage to living organisms. The eye of animals and humans is a critically exposed area and contains UV absorbing compounds like proteins, tryptophan, tyrosine, ascorbic acid and uric acid in the aqueous humour (AH) for protection. In addition, an unknown component (compound X) which causes red-shift in the UV absorbance spectrum at 254 nm has been observed in heavily exposed species like goose, which migrates at 10 000 m altitude. X is a major absorber. UV measurements confirmed the presence of a compound in geese which has higher absorption at 254 nm compared to other species. Compound X also has fluorescence activity that resembled indole-functionality. Aqueous humour samples from different species (goose, chicken, turkey) were measured by nuclear magnetic resonance spectroscopy (NMR). The proton NMR spectra did not show any specific high abundant compound in the goose eye at the aromatic region compared to the other species, thus NMR could not reveal what made the difference between in UV absorbance. Mass spectrometry with atmospheric pressure photoionization (APPI) has earlier showed that the molar mass of the compound X could be 149 g/mole, which suggests that compound X might be the indole: 5,6-dihydroxyindole (DHI). DHI has a central role in the biosynthesis of melanin which takes place in melanocyte cells. DHI tends to easily be polymerized and one of the results is a notable change in its solubility. It was not possible to obtain a suitable external standard which did not undergo auto-polymerization, mirroring the observations with the isolated compound.To further test the hypothesis of DHI being compound X, reversed phase (RP) high performance liquid chromatography (HPLC) and hydrophilic interaction liquid chromatography (HILIC) were performed. Ascorbic acid co-eluted with the most abundant peak (compound X) in RP-HPLC. In HILIC the most abundant peak was not ascorbic acid. Hence, compound X is not ascorbic acid, and subsequent experiments showed that it was neither the UV absorbing compounds tryptophan, tyrosine or uric acid. After using several analytical tools, the hypothesis that compound X is 5,6-dihydroxyindole was strengthened. However an external standard is still necessary to provide accurate information.

• Racz, Beatrix; Zawadzka, Malgorzata Elzbieta; Skytte Af Sätra, Jenny Marie; Ringvold, Amund; Rise, Frode; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Identification of “compound X” in goose aqueous humour.
• Røberg-Larsen, Hanne; Hutchinson, Sam Alex; Solheim, Stian; Wilson, Steven Ray Haakon; Lundanes, Elsa & Thorne, James L (2018). Oxysterols in breast cancer.
• Røberg-Larsen, Hanne; Sande, Maria Therese; Hutchinson, Samantha A; Solheim, Stian Kjønnås; Lundanes, Elsa; Thorne, James L & Wilson, Steven Ray Haakon (2018). Rapid determination of oxysterols in breast cancer tumors.
• Skjærvø, Øystein; Pilarova, Veronika; Khalikova, Maria; Reubsaet, Leon; Halvorsen, Trine Grønhaug; Gjelstad, Astrid; Øiestad, Elisabeth Leere; Lundanes, Elsa; Wilson, Steven Ray Haakon & Pedersen-Bjergaard, Stig (2018). Those Who Can, Teach: Pharma Stars. The Analytical Scientist.  ISSN 2051-4077.  1118, s 40- 45
• Skytte Af Sätra, Jenny Marie; Nielsen, Claus Jørgen; Van Bavel, Albert; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Developing procedures for trace analysis of small amines in water, using LC-MS and GC-MS.
• Solheim, Stian Kjønnås; Lundanes, Elsa; Wilson, Steven Ray Haakon & Røberg-Larsen, Hanne (2018). Exploring selectivity and sensitivity for oxysterol measurements using liquid chromatography-mass spectrometry (LC-MS).
• Vehus, Tore; Wilson, Steven Ray Haakon; Lundanes, Elsa; Krauss, Stefan; Halvorsen, Trine Grønhaug & Morth, Jens Preben (2018). Nano Liquid Chromatography-Tandem Mass Spectrometry Platforms for Determination of Low Abundant Wnt/Beta-Catenin Proteins in Cancer Research. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1962.
• Bjørseth, Kamilla; Wilson, Steven Ray Haakon; Brandtzaeg, Ole Kristian & Lundanes, Elsa (2017). Evaluation of exosome isolation techniques for hydrophilic interaction liquid chromatography-mass spectrometry based metabolomics.
• Demir, Deniz; Abele, Silvija; Røberg-Larsen, Hanne; Wilson, Steven Ray Haakon & Lundanes, Elsa (2017). Development of an ultrasensitive method for multiresidue screening of pharmaceutical products in environmental water samples.
• Demir, Deniz; Lundanes, Elsa; Wilson, Steven Ray Haakon; Abele, Silvija & Røberg-Larsen, Hanne (2017). Automatic capillary liquid chromatography tandem mass spectrometry method for pharmaceutical products in environmental water samples.
• Johnsen, Elin Follaug; Lundanes, Elsa; Wilson, Steven Ray Haakon & Greibrokk, Tyge (2017). High performance analytical Tools for small molecules in biosamples. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1803.
• Reinholds, Ingars; Pugajeva, Iveta; Perkons, Ingus; Lundanes, Elsa; Rusko, Janis; Ķizāne, Gunta K.; Nikolajeva, Vizma; Mutere, Olga; Petrina, Zaiga; Baumane, Larisa Kh & Bartkevics, Vadims (2017). Erratum to: Decomposition of multi-class pharmaceutical residues in wastewater by exposure to ionising radiation (International Journal of Environmental Science and Technology, (2017), 10.1007/s13762-017-1290-6). International Journal of Environmental Science and Technology.  ISSN 1735-1472.  14(8), s 1821- 1821 . doi: 10.1007/s13762-017-1325-z
• Røberg-Larsen, Hanne; Skottvoll, Frøydis Sved; Solheim, Stian; Bjørseth, Kamilla; Thorne, James L; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Oxysterols in cancer.
• Skottvoll, Frøydis Sved; Berg, Henriette Engen; Lund, Kaja; Røberg-Larsen, Hanne; Wilson, Steven Ray Haakon & Lundanes, Elsa (2017). Critical evaluation of isolation and characterization techniques of breast cancer exosomes.
• Solheim, Stian; Røberg-Larsen, Hanne; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Optimizing selectivity and sensitivity for oxysterol measurements using liquid chromatography-mass spectrometry (LC-MS).
• Sved Skottvoll, Frøydis; Lund, Kaja; Røberg-Larsen, Hanne; Berg, Henriette Sjånes; Thiede, Bernd; Lundanes, Elsa & Wilson, Steven Ray Haakon (2017). Diagnostic potential of exosomes: The purification issue.
• Abele, Silvija; Røberg-Larsen, Hanne; Dzabijeva, Diana; Demir, Deniz; Amundsen, Sunniva F.; Wilson, Steven Ray Haakon; Bartkevics, Vadims & Lundanes, Elsa (2016). Simultaneous determination of pharmaceutical product residues in water by HPLC-MS/MS using online SPE.
• Berg, Henriette Sjånes; Lundanes, Elsa; Wilson, Steven Ray Haakon & Vehus, Tore (2016). Optimization of in-house packing of nano liquid chromatography columns - How to pack low-cost nano liquid chromatography columns?. Show summary

  Liquid chromatography-mass spectrometry (LC-MS) approaches for measurement of biomarkers are increasing in popularity due to the selectivity and sensitivity. To match the detection limits of the immunoassay approaches (such as enzyme-linked immunosorbent assay (ELISA) and Western Blot (WB)), LC columns with narrow inner diameter are preferable. The goal of this work was to establish a simple and low cost slurry packing procedure to obtain 50 µm inner diameter (ID) x 150 mm particle packed nanoLC columns with comparable performance to a 75 µm ID x 150 mm commercial nanoLC column. Slurry packing with 2.6 µm solid-core reversed phase particles was performed with an in-house made pressure bomb system (< 200 bar). Column efficiency was measured as peak capacity (number of peaks separated in a gradient window, PC), calculated using peptides from tryptic digest of human serum albumin (HSA). To maintain sedimentation of particles, heat or magnetic stirring was needed. 80/20 % acetonitrile (ACN)/water as slurry solvent was found to give both the fastest packing and the most efficient columns measured as PC (89 ± 11 at 10 % of the peak height for columns packed with magnetic stirring). Nevertheless, the column performance was quite similar for all slurry solvents and packing approaches. “Pico Frit” column housings from New Objective and two frit-making procedures (polymerization and sintering of silica particles) for standard column housings were compared, but none outperformed the others. The PC of the commercial column packed with the same material as the in-house packed columns, was approximately 30 % higher than the best performing in-house packed column (102 vs 136). However, the retention time repeatability between replicates was equal to the commercial column for most columns packed with 80/20 % ACN/water. In conclusion, this work presents a fast and low cost packing procedure of nanoLC columns with similar performance to commercial nanoLC columns.

• Berg, Henriette Sjånes; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Optimization of in-house packed nano-LC columns for peptide separations.
• Brandtzæg, Ole Kristian Merkesvik; Johnsen, Elin Follaug; Røberg-Larsen, Hanne; Leknes, Siri; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Robust nano liquid chromatography mass spectrometry system for targeted determination of oxytocin in human serum/plasma..
• Dowood, Rua Kareem; Wilson, Steven Ray Haakon; Lundanes, Elsa & Johansen, Elin (2016). Determination of 3'-phosphoadenosine-5'-phosphosulfate in cells using hydrophilic interaction liquid chromatography and mass spectrometry. Show summary

  3'-Phosphoadenosine-5'-phosphosulfate (PAPS) is the universal donor of sulfate to sulfotransferases, a large group of enzymes that transfer sulfate to various molecules in the sulfation pathway. Methods that have been previously used to determine this important metabolite lack in specificity. The aim of the project was to develop a method for determining PAPS in cells and cellular fractions, using hydrophilic interaction liquid chromatography and mass spectrometry. The developed method gave a retention time under 10 minutes, acceptable chromatographic efficiency and satisfactory repeatability in measurements. The method was able to separate PAPS from ATP and ADP, which could interfere with PAPS signal in the MS as they share mass spectrometric features. In addition, a simple sample preparation procedure was developed using ultra centrifugal filters. The method was evaluated regarding linearity, carry-over, within- and between-day precision etc., and PAPS levels was estimated in MDCK cell lines and their Golgi fractions, also following treatment with sodium chlorate (a PAPS synthesis inhibitor). The combination of the ultra centrifugal filtration, as a sample preparation step, ZIC-pHILIC and ESI-MS detection was found to be a suitable technique for the analysis of PAPS.

• Poothong, Somrutai; Lundanes, Elsa; Thomsen, Cathrine & Haug, Line Småstuen (2016). Perfluoroalkyl substances; levels and profiles in human serum, plasma, and whole blood in a Norwegian cohort.
• Røberg-Larsen, Hanne; Lund, Kaja; Sved Skottvoll, Frøydis; Gregus, Michael; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). 27-hydroxycholesterol in cancer exosomes – potential new separation method?.
• Røberg-Larsen, Hanne; Lund, Kaja; Sæterdal, Kristina Erikstad; Solheim, Stian; Vehus, Tore; Solberg, Nina; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Capillary LC mass spectrometric detection of 27-hydroxycholesterol in breast cancer exosomes.
• Røberg-Larsen, Hanne; Lundanes, Elsa; Wilson, Steven Ray Haakon & Krauss, Stefan (2016). High sensitivity measurements of side-chain oxysterols using liquid chromatography mass spectrometry. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. ?.
• Sandvik, Trude Athammer; Husa, Asgeir & Lundanes, Elsa (2016). Development of a routine method for determination of vitamin K1 in serum based on semi-automated solid phase extraction and supercritical fluid chromatography mass spectrometry.
• Skjærvø, Øystein; Brandtzæg, Ole Kristian Merkesvik; Martinsen, Ørjan Grøttem; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Characterization of polymer layer open tubular columns for liquid chromatography and open tubular enzyme reactors for on-line sample preparation.
• Skjærvø, Øystein; Wilson, Steven Ray Haakon; Lundanes, Elsa; Brandtzaeg, Ole Kristian & Martinsen, Ørjan Grøttem (2016). Characterization of open tubular enzyme reactors and polymer layer open tubular columns for liquid chromatography. Show summary

  The structure, thickness and characteristics of liquid chromatography (LC) column materials are central factors regarding their performance. However, miniaturized capillaries (sub 20.0 μm inner diameter, typically used for small sample analysis) are difficult to characterize. The main goal of this work was to develop a simple, yet accurate, electrochemical impedance spectroscopy (EIS) method for characterization of the polymer layers of narrow open tubular (OT) columns. In situ prepared polymerized capillaries (poly(styrene-co-divinylbenzene) and poly(2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone) OT capillaries were characterized. The developed EIS method proved simplicity in terms of providing layer thickness determinations compared to determination by scanning electron microscope (SEM). In addition, screening of the polymer layer homogeneity throughout the capillaries was simplified by EIS. The porosity of the polymer layer OT columns was investigated by EIS, SEM and sample loading capacity measurements (using LC). Under pore-blocking conditions, none of the polymerized capillaries could be shown to have porosity, so it was assumed that a thin polymer layer is beneficial for both types of capillaries in order to provide a high surface area, i.e. more available functional groups. EIS methods have not been published for capillary characterization by date. However, the method showed promising results and has great potential for future applications regarding characterization and preparation optimization of polymerized capillaries.

• Smetop, Tone; Lundanes, Elsa; Vehus, Tore & Wilson, Steven Ray Haakon (2016). Silica-based monolithic pre-columns in miniaturized liquid chromatography. Show summary

  In miniaturized liquid chromatography (LC) an online clean up system and/or pre-concentration step, is essential to increase large loading capacity, loading speed could be used so the analysis is faster, and it is more robust (i.e. sample cleanup of salts and excess reagents. In this study the goal was to make efficient and robust reversed phase (RP) silica-based monolithic pre-columns with an inner diameter (ID) of ≤50 µm to be used in a switching system with an online pre-column. The silica skeleton was found to be the trickiest part to make in these columns, because they easily shrink and crack. Different procedures were investigated and a procedure was found to give the thinnest skeleton (0.4 µm) without shrinking/cracking. The solutions found to give the most homogenous skeleton was obtained with this procedure: Pre-treated and silanized fused silica capillaries were filled with a polymerization solution consisting of 4.5 mL tetramethoxysilane (TMOS), 1.06 g polyethylene glycol (PEG) (Mn = 10 000) and 10 mL aqueous acetic acid (0.01 M), which was allowed to react at 40 oC for 24 h. The capillary was subsequently filled with ammonium hydroxide (0.1 M) and allowed to react at 120 oC for 3h, before the skeleton was dried at 330 oC for 24 h. The reason for absence of shrinking/cracking was the final heating step at 330 oC. A “thiol-ene” click reaction was found to be an easy way to link the stationary phase (SP) to the skeleton. First vinylfunctionalization of the skeleton was carried out with vinyltrimethoxysilane (VTMS) followed by a click reaction with octanethiol, that gave a RP column with C8 as SP. Columns with plate height down to 70 µm were made, tested with a simple LC-UV system. One of the columns was successfully implemented in an LC-Mass Spectrometry (MS) system as a pre-column in combination with a 50 µm x 15 cm Accucore (2.6 µm) RP analytical column. A peak capacity of 79 was obtained, compared to a system with a commercial packed pre-column that gave a peak capacity of 47(measured at half peak height). Many procedures presented in papers were investigated and they are not good enough to reproduce a successful silica- based monolithic column.

• Smetop, Tone; Vehus, Tore; Wilson, Steven Ray Haakon & Lundanes, Elsa (2016). Silica-based monolithic pre-columns in miniaturized liquid chromatography.
• Sæterdal, Kristina E.; Vehus, Tore; Røberg-Larsen, Hanne; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). CYP27A1 – its relation to oxysterols and cancer, and analytical challenges.
• Sæterdal, Kristina Erikstad; Vehus, Tore; Røberg-Larsen, Hanne; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Determination of CYP27a1 in biological samples using nano liquid chromatography mass spectrometry. Show summary

  The cytochrome P450 enzyme, CYP27a1, converts cholesterol into 27-hydroxycholesterol, and both the metabolite and the enzyme are associated with breast cancer, promoting proliferation and metastasis. CYP27A1 is enriched in cancer tissues, and the amount of CYP27a1 correlates to tumor grade. Hence, CYP27a1 is a potential biomarker, and a method for determination and quantification is needed. Antibody assays shows limited performance, and therefore the goal of this work was to develop a nano liquid chromatography mass spectrometry (LC-MS) method for determination of CYP27a1. A sample preparation workflow for CYP27a1 in cell samples was investigated. CYP27a1 was identified by nano LC-MS in MDA-MB-231 breast cancer cells by fractionating cell lysates using gel electrophoresis. Enrichment of CYP27a1 in cell samples using immunoprecipitation, an antibody based method for protein extraction, did not provide adequate identification. However the former method works when looking at other proteins, and this confirms that there are limitations in using antibody based methods for determination and quantification of CYP27a1.

• Vehus, Tore; Lundanes, Elsa; Røberg-Larsen, Hanne; Brandtzaeg, Ole Kristian & Wilson, Steven Ray Haakon (2016). Open tubular liquid chromatography-mass spectrometry: a powerful and versatile tool for bioanalysis.
• Wilson, Steven Ray Haakon; Brandtzaeg, Ole Kristian; Lundanes, Elsa & Vehus, Tore (2016). Open Tubular Liquid Chromatography-Mass Spectrometry: a tool for cancer biomarker discovery in ultrasmall samples.
• Wilson, Steven Ray Haakon; Lundanes, Elsa; Vehus, Tore & Røberg-Larsen, Hanne (2016). On-line sample preparation and liquid chromatography using "sub-chip" columns for ultra-sensitive proteomics.
• Wilson, Steven Ray Haakon; Vehus, Tore; Røberg-Larsen, Hanne & Lundanes, Elsa (2016). “Sub-chip” liquid chromatography-mass spectrometry for measuring oxysterols and related proteins.
• Foseid, Lena; Vogt, Rolf David; Nielsen, Claus Jørgen; Lundanes, Elsa & Gundersen, Cathrine Brecke (2015). Determination of MEA-nitramine in Soil Water and Assessing the Sorption Potential of MEAnitramine to Soil. Show summary

  Small amounts of amines are emitted with the flue gas from amine based carbon capture plants. The amines atmospheric degradation have been studied in detail. The environmental impact of the degradation products, e.g. the possibly carcinogenic and mutagenic nitramines, is however insufficiently studied. This thesis investigates the capacity of nitramines to sorb to soil, depending on the soils physiochemical characteristics. To accomplish this, the analytical challenges with regards to determination of nitramines in soil water had to be solved. Soil samples were collected in the vicinity of Technology Center Mongstad (TCM) (~15 km) as this is a possible future deposition site for nitramines. The sampling sites were chosen with the aim of collecting soils with different physiochemical properties, with special emphasis on the content of soil organic matter and soil texture. All of the collected soil samples (n=16) were analysed for explanatory parameters expected to influence soil sorption, such as organic matter (OM) content, dissolved natural organic matter (DNOM) leached from the soil, texture, mineralogy, pH and conductivity. A selection of the samples (n=5) were used in soil sorption experiments to assess the sorption potential of N-Nitroethanolamine (MEA-nitramine). A batch experimental set-up was used, and sorption was measured as loss of MEA-nitramine from the aqueous phase after being added at known concentrations (24 h equilibrium). For these samples, elemental composition was also determined. Possible correlations between the sorption coefficients and the soils physiochemical characteristics were assessed. Determination of MEA-nitramine in soil water with LC-MS/MS proved to be a challenge due to matrix effects. Different calibration methods with and without matrix matched calibration solutions were tested. Another nitramine, N-nitromethylamine (MMA-nitramine), was tested as internal standard. Additionally, a couple of sample pretreatment techniques were tested to try and separate the analyte from the matrix (solid phase extraction (SPE), filtration). Sorption partitioning coefficients between soil and aqueous phase were determined (Kd) and the results imply that a significant amount of MEA-nitramine will remain in the aqueous phase. Correlation between the partition coefficients for the five studied soils and the soils OM content was observed (r > 0.788). Loss of internal standard (MMA-nitramine) was also observed, this loss correlated strongly with the DNOM concentration in the sample supernatant (r = 0.9924), implying that sorption to DNOM could be important. The relation between sorption and OM content implies that sorption will generally be higher in the top soil (organic) horizons than in the lower (mineral) soil horizons. As deposition of atmospherically formed nitramines will be to the soil surface, this can serve to hinder mobility. The analytical determination method for nitramines in soil water was improved, although not considered satisfactory at the end of the study. Major improvement resulted from the used of matrix matched calibration curves, which compensate for both ion suppression/enhancement effects and possible sorption to DNOM. Even though this is time- and labour consuming, the method was proven more successful than attempts made to separate the analyte from the matrix prior to analysis. The used of MMA-nitramine as an internal standard for determination of MEA-nitramine was not successful, possibly due to the difference in retention time and therefore possible different effect from the matrix components. An isotope-labelled internal standard should therefore be acquired. Investigation into other sample pretreatments could also be of interest. Note that previously reported sorption partition coefficients for sorption of nitramines to soil could be inaccurate if matrix matched calibration curves were not employed.

• Brandtzæg, Ole Kristian Merkesvik; Hustoft, Hanne Kolsrud; Vehus, Tore; Greibrokk, Tyge; Krauss, Stefan; Reubsaet, Leon; Lundanes, Elsa & Wilson, Steven Ray Haakon (2015). On-line protein digestion and peptide separation using “ultra-nano” LC-MS.
• Gundersen, Cathrine Brecke; Foseid, Lena; Zhu, Liang; Lundanes, Elsa & Vogt, Rolf David (2015). Sorption potential of Nitramines to soils - Methodical challenges using LC-MS/MS.
• Johnsen, Elin Follaug; Wilson, Steven Ray Haakon; Leknes, Siri & Lundanes, Elsa (2015). Highly automated platform for simultaneous identification of all classes of neurotransmitters by hydrophilic interaction liquid chromatography-MS.
• Lausund, Kristian Blindheim; Wilson, Steven Ray Haakon; Gorbitz, Carl Henrik; Lundanes, Elsa & Nilsen, Ola (2015). Deposition of organic-inorganic hybrid films of Zr-1,4-BDC by ALD.
• Lausund, Kristian Blindheim; Wilson, Steven Ray Haakon; Gorbitz, Carl Henrik; Lundanes, Elsa & Nilsen, Ola (2015). Nano-filters for Blood Sample Analysis.
• Lausund, Kristian Blindheim; Wilson, Steven Ray Haakon; Gorbitz, Carl Henrik; Lundanes, Elsa & Nilsen, Ola (2015). Nano-filters for blood sample analysis.
• Lausund, Kristian Blindheim; Wilson, Steven Ray Haakon; Gorbitz, Carl Henrik; Lundanes, Elsa & Nilsen, Ola (2015). Porous inorganic-organic hybrid materials by ALD.
• Record, Rena Samantha; Lundanes, Elsa; Wilson, Steven Ray Haakon & Vehus, Tore (2015). Monolithic pre-columns in miniaturized liquid chromatography. Show summary

  Poly(styrene co-divinylbenzene) (PS-DVB) monolithic pre-columns of 50 μm inner diameter (ID) were developed for peptides and small molecules enrichment intended for use in automated miniaturized liquid chromatography-mass spectrometry (LC-MS) column switching system as alternative to 50 μm ID poly(butyl methacrylate-co-ethylene dimethacrylate) (BMA-EDMA) monoliths. Monomer/porogen ratio, percentage of good solvent, polymerization temperature, and polymerization time, and thermal initiator, were investigated in order to optimise the monolithic structure with a high surface area and good permeability. The efficiency was measured on 10 cm long column using a simple liquid chromatography ultraviolet (LC-UV) test system with toluene as the test analyte. In general, increasing polymerization temperature lead to a monolith with a higher number of small pores and backpressure. A ratio of 40/60 between monomers and porogens was required for a full structure of monolith. The columns made with LP yielded a better efficiency compare to the commonly used 2,2'-azobis(2-methylpropionitrile (AIBN) for both PS-DVB and BMA-EDMA monoliths. Reaction time strongly affected column efficiency. The best monolithic PS-DVB pre-columns were prepared, using a binary porogenic solvent of toluene (9%) and 1-decanol (51%), lauryl peroxide (LP) as initiator and polymerization temperature of 73°C for 2 hours (plate height, H = 90 μm). PS-DVB monoliths which provided good efficiency for toluene with reasonably backpressure gave a narrow elution peak for luteinizing hormone releasing hormone (LHRH) without breakthrough using gradient elution (10 cm length). The developed PS-DVB monolith gave better peak shape, trapping ability and loadability for peptides than a BMA-EDMA monolith using the solid phase extraction tandem mass spectrometry (SPE-MS/MS) system. When combining a PS-DVB monolithic pre-column (50 μm × 4 cm, 500 nl/min flow rate) with a porous layer open tubular (PLOT) PS-DVB analytical column (~0.75 μm film thickness, 10 μm × ~5 m, 40 nl/min flow rate), a longer retention time (tR) (~48 min) than expected was obtained. Thus, further development of a suitable pre-column for this system is needed.

• Røberg-Larsen, Hanne; Lund, Kaja; skottvoll, Frøydis S; Krauss, Stefan; Lundanes, Elsa & Wilson, Steven Ray Haakon (2015). Oxysterols in exosomes.
• Røen, Bent Tore; Sellevåg, Stig Rune & Lundanes, Elsa (2015). Quantification of Nerve Agent Markers – by Online SPE‐LC‐MS. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1630.
• Sandvik, Trude Athammer & Lundanes, Elsa (2015). Development of a routine method for determination of vitamin K1 in serum based on semi-automated solid phase extraction and supercritical fluid chromatography mass spectrometry.
• Vesterdal, Caroline; Røberg-Larsen, Hanne; Wilson, Steven Ray Haakon; Greibrokk, Tyge & Lundanes, Elsa (2015). Comparing methods for sensitive determination of Hedgehog active oxysterols. Show summary

  Oxysterols in biological samples of limited size are present in low concentrations thus sensitive methods are advantageous. Derivatization of oxysterols prior to liquid chromatography (LC) mass spectrometry (MS) analysis is a common, however a laborious approach. The possibility to reduce the extent of sample preparation by formation of adducts between oxysterols and mobile phase additives (e.g. ammonium acetate) were investigated. Stable adduct ion signals were not obtained with the use of the MS instruments available. However, loss of water ions ([Oxysterol+H-H2O]+ and [Oxysterol+H-2H2O]+, m/z 385.35 and m/z 367.34) were observed when diluting oxysterol standards with ammonium formate (2.5 mM) and formic acid (0.25%) in methanol (MeOH). Under these conditions no easy recognizable fragmentation pattern was observed in tandem MS mode due to clustering of ions in the low mass area when fragmentation energy was applied. Another challenge with the analysis of native oxysterols with a nanoLC system was adsorption to surfaces, especially to fused silica capillaries. Silanization of the fused silica capillaries reduced the issue, but nowhere near satisfactory. It was considered unfeasible to determine native oxysterols with high sensitivity using nanoLC due to the large carry-over issues. Derivatization is therefore recommended when analyzing oxysterols with nanoLC. An on-line automatic filtration filter back-flush solid phase extraction liquid chromatography tandem mass spectrometry (AFFL-SPE-LC-MS/MS) method for determination of Girard T derivatized 24S-hydroxycholesterol, 25-hydroxycholesterol, 27-hydroxycholesterol, and 22S-hydroxycholesterol was modified for analysis of exosome samples. Best separation of oxysterol isomers was obtained with an ACE 3 C18 (0.1 mm ID × 150 mm, 3μm, 100 Å) column with a column temperature of 15°C and by using a mobile phase gradient from 0.1/25/75 (v/v/v %) FA/H2O/MeOH to 0.1/10/90 (v/v/v %) FA/H2O/MeOH in 25 minutes. The method was used for analyses of exosome samples obtained with the use of different isolation techniques to find a suitable procedure for exosome isolation.

• Wilson, Steven Ray Haakon; Lundanes, Elsa; Vehus, Tore; Hustoft, Hanne Kolsrud & Brandtzaeg, Ole Kristian (2015). Open tubular enzyme reactors and separation columns for accelerated and sensitive proteomics.
• Wilson, Steven Ray Haakon; Lundanes, Elsa; Vehus, Tore; Røberg-Larsen, Hanne; Johnsen, Elin Follaug & Brandtzaeg, Ole Kristian (2015). Ultra-trace analysis of signal pathways: proteomics, lipidomics and neurotransmitters.
• Abele, Silvija; Røgeberg, Magnus; Wilson, Steven Ray Haakon; Lundanes, Elsa & Greibrokk, Tyge (2014). Development of new materials for chromatography - HILIC-PLOT columns for LC-MS analysis of metabolites of cancer stem cells..
• Bergh, Marianne Skov-Skov; Lundanes, Elsa; Øiestad, Åse Marit Leere & Bogen, Inger Lise (2014). Utvikling av væskekromatografi-massespektrometri- metoder for bestemmelse av nevrotransmittere i dialysat og hjernevev fra rotte og mus.
• Brandtzaeg, Ole Kristian; Hustoft, Hanne Kolsrud; Wilson, Steven Ray Haakon; Greibrokk, Tyge & Lundanes, Elsa (2014). Open Tubular Enzyme Reactors (OTERs) for On-line Protein Digestion in Liquid Chromatography Mass Spectrometry Proteomics. Show summary

  Sample preparation in bottom-up proteomics consists of denaturation, reduction and alkylation of the proteins, before enzymatic digestion of the proteins into peptides. The rate limiting step is the enzymatic digestion, and digestion overnight is recommended. Hence, for faster analysis, the digestion time should be reduced. The main focus of this master thesis was the development of 20 μm inner diameter (ID) open tubular enzyme reactors (OTERs) based on 2-hydroxyethyl methacrylate-co-vinyl azlactone (HEMA-VDM) for on-line protein digestion of limited sample sizes in a nano liquid chromatography (LC) - mass spectrometry (MS) system. Monolithic solid phase extraction (SPE) pre-columns based on butyl methacrylate (BuMa) and polystyrene divinylbenzene (PS-DVB) were prepared in 50 μm ID capillaries and used for trapping of peptides generated by the OTER. These peptides were then separated using 10 μm ID PS-DVB porous layer open tubular (PLOT) columns. The developed OTER was prepared by polymerization using a polymerization mixture consisting of HEMA and VDM as monomer, 1-heptanol or 1-decanol as porogen, and 2,2´azobis(2-methylpropinonitrile) (AIBN) as initiator. Short OTERs were prepared with 1-decanol as porogen, while for longer OTERs, 1-heptanol was used. The sample was loaded onto the OTER with a loading buffer consisting of 50 mM NH4OAc pH 8.75 with 4 % acetonitrile (ACN). A trapping time of 4 min from the OTER to the SPE column was found to be optimal (for the short OTER) using the manual LC-MS-system (developed by Hanne K. Hustoft). The run-to-run retention time repeatability in this system, was 0.25-0.44 % in relative standard deviation (RSD %), and 300 attomoles of targeted recombinant progastrin-releasing peptide isoform 1 (ProGRP) could be detected. The developed long OTER, immobilized with Trypsin/endoproteinase Lys-C (T/L) gave sequence coverages (SQ %) up to 95 % of standard proteins. The optimal reactor temperature during digestion and the optimal digestion time was 37 ºC and 30 min, correspondingly. The OTER could be integrated in an automated LC-MS-system (Hanne K. Hustoft and set up by Tore Vehus), where the within and between digestion repeatability were satisfactory. About 1500 proteins were identified in a single analysis when injecting 1 μg of a human cell lysate sample using the OTER in the automated system.

• Hustoft, Hanne Kolsrud; Brandtzæg, Ole Kristian Merkesvik; Torsetnes, Silje Bøen; Greibrokk, Tyge; Reubsaet, Leon; Wilson, Steven Ray Haakon & Lundanes, Elsa (2014). Development of a nanoproteomic platform with integrated immunocapture and enzymatic digestion for on-line detection of the low abundant cancer biomarker PROGRP.
• Hustoft, Hanne Kolsrud; Lundanes, Elsa; Wilson, Steven Ray Haakon; Reubsaet, Leon & Greibrokk, Tyge (2014). Accelerating enzymatic protein digestion and on-line nano liquid chromatography-mass spectrometry based proteomics.
• Hustoft, Hanne Kolsrud; Wilson, Steven Ray Haakon; Vehus, Tore; Røgeberg, Magnus; Brandtzæg, Ole Kristian Merkesvik; Greibrokk, Tyge & Lundanes, Elsa (2014). Open tubular enzyme reactors and LC columns for high performance protein analysis.

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