Tore Sandnes Vehus

• Nielsen, Henrik Kofoed; Vehus, Tore; Rudra, Souman & Kristiansen, Nils Randulf (2022). Chapter 9 - Biomass production, storage, and pretreatment for the production of solid biofuels. In Gomez Castro, Fernando & Gutierrez-Antonio, Claudia (Ed.), Biofuels and Biorefining Volume 1: Current Technologies for Biomass Conversion. Elsevier. ISSN 9780128241165. p. 339–380. doi: 10.1016/B978-0-12-824116-5.00003-9.
• Skomedal, Gunstein; Vehus, Tore; Kanas, Nikola; Singh, Sathya Prakash; Einarsrud, Mari-Ann & Wiik, Kjell [Show all 7 contributors for this article] (2019). Long term stability testing of oxide unicouple thermoelectric modules. Materials Today: Proceedings. ISSN 2214-7853. 8(2), p. 696–705. doi: 10.1016/j.matpr.2019.02.070. Full text in Research Archive
• Surup, Gerrit Ralf; Vehus, Tore; Eidem, Per Anders; Trubetskaya, Anna & Nielsen, Henrik Kofoed (2019). Characterization of renewable reductants and charcoal-based pellets for the use in ferroalloy industries. Energy. ISSN 0360-5442. 167, p. 337–345. doi: 10.1016/j.energy.2018.10.193.
• 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, p. 104–110. doi: 10.1016/j.chroma.2017.08.071.
• Berg, Henriette Sjånes; Sæterdal, Kristina Erikstad; Smetop, Tone; Rozenvalds, Rūdolfs; Brandtzaeg, Ole Kristian & Vehus, Tore [Show all 8 contributors for this article] (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, p. 111–119. doi: 10.1016/j.chroma.2017.03.043.
• 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), p. 232–239. Full text in Research Archive
• Røberg-Larsen, Hanne; Lund, Kaja; Sæterdal, Kristina Erikstad; Solheim, Stian; Vehus, Tore & Solberg, Nina [Show all 9 contributors for this article] (2017). Mass spectrometric detection of 27-hydroxycholesterol in breast cancer exosomes. Journal of Steroid Biochemistry and Molecular Biology. ISSN 0960-0760. 169, p. 22–28. doi: 10.1016/j.jsbmb.2016.02.006.
• 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.
• Vehus, Tore; Røberg-Larsen, Hanne; Waaler, Jo; Aslaksen, Sigrid; Krauss, Stefan & Wilson, Steven Ray Haakon [Show all 7 contributors for this article] (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
• Johnsen, Elin Follaug; Brandtzaeg, Ole Kristian; Vehus, Tore; Røberg-Larsen, Hanne; Bogoeva, Vanya & Ademi, Ornela [Show all 9 contributors for this article] (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, p. 106–111. doi: 10.1016/j.jpba.2015.12.010.
• 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), p. 1799–1815. doi: 10.4155/bio.15.92.
• Olsen, Peter Angell; Solberg, Nina; Lund, Kaja; Vehus, Tore; Gelazauskaite, Monika & Wilson, Steven Ray Haakon [Show all 7 contributors for this article] (2014). Implications of targeted genomic disruption of β-catenin in B×PC-3 pancreatic adenocarcinoma cells. PLOS ONE. ISSN 1932-6203. 9(12). doi: 10.1371/journal.pone.0115496.
• Hustoft, Hanne Kolsrud; Vehus, Tore; Brandtzæg, Ole Kristian Merkesvik; Krauss, Stefan; Greibrokk, Tyge & Wilson, Steven Ray Haakon [Show all 7 contributors for this article] (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
• Røberg-Larsen, Hanne; Lund, Kaja; Vehus, Tore; Solberg, Nina; Vesterdal, Caroline & Misaghian, Dorna [Show all 10 contributors for this article] (2014). Highly automated nano-LC/MS-based approach for thousand cell-scale quantification of side chain-hydroxylated oxysterols. Journal of Lipid Research. ISSN 0022-2275. 55(7), p. 1531–1536. doi: 10.1194/jlr.D048801.
• Røgeberg, Magnus; Vehus, Tore; Grutle, Lene; Greibrokk, Tyge; Wilson, Steven Ray Haakon & Lundanes, Elsa (2013). Separation optimization of long porous-layer open-tubular columns for nano-LC-MS of limited proteomic samples. Journal of Separation Science. ISSN 1615-9306. 36(17), p. 2838–2847. doi: 10.1002/jssc.201300499.

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• Chandra Pratama Putra, Jouvan; Vehus, Tore & Nielsen, Henrik Kofoed (2023). A Review on Electron-Hole Pairs Mechanism in Dark Photocatalysis.
• Berg, Henriette Engen; Skottvoll, Frøydis Sved; Bjørseth, Kamilla; Sæterdal, Kristina Erikstad; Brandtzaeg, Ole Kristian & Vehus, Tore [Show all 11 contributors for this article] (2018). Development of nanoLC column technology for proteomic studies . Show summary

  Background NanoLC has emerged as a major technique in proteomics due to improved sensitivity, which enables analysis of small sample volumes and low concentrations. In our group (Bioanalytical chemistry, BACH) we focus on the development of column technology, including porous layer open tubular (PLOT) columns and self-packing of columns for proteomic applications. Methods The PLOT columns were used for both on-line digestion (enzyme reactors) and separations (10 µm ID, PS-DVB with ODS). Enzyme reactors (20 µm ID and multi-PLOT columns (~8 µm ID)) were immobilized with trypsin and Lys-C for protein digestion. We also compared self-packed columns of 50 µm ID (2.6 µm C18 core-shell particles) to a commercial column (75 µm ID). The columns were used for detection of CYP27a1 in MDA-MB-231 (breast cancer) cells, and biomarker candidates in MDA-MB-231 and glioblastoma multiforme (brain cancer) exosomes. For exosome isolation (cell culture medium), ultracentrifugation (“golden standard”) was compared to a Total Exosome Isolation Reagent from Thermo Fisher regarding protein yield and purity. Results Our PLOT columns were successfully employed for proteins, metabolites and peptides with attogram detection limits and peak capacities around 250 [1]. The enzyme reactors provided sufficient digestion in ~5 minutes compared to overnight digestions (common in off-line protocols) [2]. Furthermore, a quantitative method of the neurotoxin ricin was developed using the multi-PLOT to reduce manual sample handling [3] . The self-packed columns obtained peak capacities comparable to the commercial nanoLC column for peptide separations [4]. The self-packed columns were used for the targeted detection of CYP27A1 (potential breast cancer biomarker) in MDA-MB-231 cells. In the recent exosome study, exosomes were present and biomarker candidates were identified. However, the characterization techniques are in our hands not satisfactory. Conclusions We have successfully developed sensitive nanoLC column formats for proteomic applications.

• Vehus, Tore & Surup, Gerrit Ralf (2018). Investigation of bio-oil from high-temperature pyrolysis of spruce.
• Vehus, Tore; Skomedal, Gunstein; Kanas, Nikola & Middleton, Peter Hugh (2018). Hot side electrical contacts for oxide thermoelectric modules.
• Brandtzaeg, Ole Kristian; Levernæs, Maren Christin Stillesby; Halvorsen, Trine Grønhaug; Reubsaet, Leon; Røen, Bent Tore & Vehus, Tore [Show all 9 contributors for this article] (2018). Online sample processing systems for targeted nano liquid chromatography mass spectrometry bioanalysis.
• 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.
• Berg, Henriette Sjånes; Bjørseth, Kamilla; Sæterdal, Kristina Erikstad; Smetop, Tone; Skottvoll, Frøydis Sved & Vehus, Tore [Show all 8 contributors for this article] (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.

• Surup, Gerrit Ralf; Nielsen, Henrik Kofoed; Vehus, Tore & Eidem, Per-Anders (2017). Comparison of Two Processes to Decrease CO2 Reactivity of Biochar for Metallurgical Industry.
• Berg, Henriette Engen; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Optimization of in-house packed nano-LC columns for peptide separations in clinical medicine. Show summary

  Early detection of biomarkers for diseases, such as cancer, is one of the most challenging and important goals in clinical medicine [1]. In modern protein analysis, mass spectrometry (MS) with electrospray ionization (ESI) has increased in popularity (compared to typical immunoassay methods) because of the sensitivity, universality, and low false positive rate. However, the MS is dependent of chromatographic separation of biological samples to lower the complexity (reduced number of analytes for the MS to handle per time unit). In this regard, the goal is an effective separation with high peak capacity (for gradient elution) and sensitivity to be able to detect possible biomarkers in or low concentrations and/or low sample volumes. Nano-LC columns can provide high sensitivity because of the low inner diameter (ID) and compatibility with ESI-MS, but the scarcity of commercial <75 µm ID packed columns limits the separation principles available. In pre-clinical research, self-packing of nano-LC columns can increase the flexibility in assessing (novel) separation materials to a low cost. In the present study, the packing process has been optimized to obtain sensitive and efficient packed columns (50 µm ID) for peptide separations with comparable performance to commercial nano-LC columns. In addition, PicoFrit columns with integrated emitter from New Objective (Woburn, MA, USA) will be examined to evaluate the potential reduction in extra-column band broadening.

• Surup, Gerrit; Nielsen, Henrik Kofoed; Vehus, Tore & Eidem, Per Anders (2016). Biochar from medium pyrolysis temperatures for smelting plant applications.
• Vehus, Tore (2016). Utvikling og bruk av ny C18 funksjonalisert silika i porøse opne røyrkolonner (PLOT).
• Wilson, Steven Ray Haakon; Vehus, Tore; Røberg-Larsen, Hanne & Lundanes, Elsa (2016). “Sub-chip” liquid chromatography-mass spectrometry for measuring oxysterols and related proteins.
• 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.
• 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; Lundanes, Elsa; Vehus, Tore & Røberg-Larsen, Hanne (2016). On-line sample preparation and liquid chromatography using "sub-chip" columns for ultra-sensitive proteomics.
• Røberg-Larsen, Hanne; Lund, Kaja; Sæterdal, Kristina Erikstad; Solheim, Stian; Vehus, Tore & Solberg, Nina [Show all 9 contributors for this article] (2016). Capillary LC mass spectrometric detection of 27-hydroxycholesterol in breast cancer exosomes.
• 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.
• Berg, Henriette Sjånes; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Optimization of in-house packed nano-LC columns for peptide separations.
• Smetop, Tone; Vehus, Tore; Wilson, Steven Ray Haakon & Lundanes, Elsa (2016). Silica-based monolithic pre-columns in miniaturized liquid chromatography.
• 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.
• Brandtzæg, Ole Kristian Merkesvik; Hustoft, Hanne Kolsrud; Vehus, Tore; Greibrokk, Tyge; Krauss, Stefan & Reubsaet, Leon [Show all 8 contributors for this article] (2015). On-line protein digestion and peptide separation using “ultra-nano” LC-MS .
• Hustoft, Hanne Kolsrud; Wilson, Steven Ray Haakon; Vehus, Tore; Røgeberg, Magnus; Brandtzæg, Ole Kristian Merkesvik & Greibrokk, Tyge [Show all 7 contributors for this article] (2014). Open tubular enzyme reactors and LC columns for high performance protein analysis.
• Vehus, Tore; Greibrokk, Tyge; Lundanes, Elsa & Wilson, Steven Ray Haakon (2014). Proteomic Analysis of the Wnt/beta-catenin Pathway.
• Vehus, Tore; Røgeberg, Magnus; Grutle, Lene; Greibrokk, Tyge; Wilson, Steven Ray Haakon & Lundanes, Elsa (2014). Bottom-up proteomikk med «open layer tubular column» for små prøver – applikasjonar og utvikling.
• Vehus, Tore (2007). Performing Quantitative Determination of Low-Abundant Proteins by Targeted Mass Spectrometry Liquid Chromatography . In Aliofkhazraei, Mahmood (Eds.), Mass spectrometry. IntechOpen. ISSN 978-953-51-3224-0. p. 79–94. doi: 10.5772/intechopen.68713.
• 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. Department of Chemistry Faculty of Mathematics and Natural Sciences. 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.

• 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. Universitetet i Oslo. ISSN 1501-7710. 2018(1962).
• 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. Universitetet i Oslo. 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.

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

• 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? Universitetet i Oslo. 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.

• Record, Rena Samantha; Lundanes, Elsa; Wilson, Steven Ray Haakon & Vehus, Tore (2015). Monolithic pre-columns in miniaturized liquid chromatography. Universitetet i Oslo. 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.

• Vehus, Tore (2012). Drug target deconvolution in cancer cells using liquid chromatography, fluorescence polarization and mass spectrometry. Universitetet i Oslo. Show summary

  Drugs are important in curing diseases, and in the latter decade, research in the use of drugs to cure cancer has grown exponentially. There are thousands of drug candidates that go through screening processes each year, but only a handful reach the clinical stage, and in the end get patented for use in treatment of diseases. One of the major difficulties today is to know if the drug binds to the desired target. Identifying the target is termed drug target deconvolution. Existing drug target deconvolution strategies have limitations, hence there is a need for a new/complementary methodology, with a high degree of throughput, versaitility and reliability. We propose a method which combines liquid chromatography (LC) in three orthogonal dimensions together with fluorescence polarization (FP) and mass spectrometry (MS) to identify target proteins in complex mixtures. Results show that FP applied on fluorecein-tagged drugs is a robust, sensitive and spesific technique to identify protein-drug binding in both standards and complex samples. Study of commercially available LC columns – SEC, HIC and mixed mode IEX under non-denaturating conditions, in three dimensions indicated a 90 % orthogonality between each dimension and a total peak capacity of ~3000. Combining LC, FP and LC-MS has shown that target identification of small molecule inhibitor XAV939 in a protein standard mixture is possible. Preliminary results indicate that target identification in SW480 colon cancer cells using the same techniques is viable. Current work indicate that it is possible to measure protein-drug binding with FP on non-tagged Wnt-inhibitors, both in protein standard samples and complex cell lysates.

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