Tore Sandnes Vehus

• Jabbari, Shahla Ghaffari; Domínguez, Jose Fermoso; Sufuentes, Sandra Rodríguez; Nyberg, Svein Olav Glesaaen; Vehus, Tore & Nielsen, Henrik Kofoed (2026). A Time-Resolved Analysis of VOCs and VVOCs from Interior Wood Materials in Low-Ventilation Environments. Forests. 17(8). doi: 10.3390/f17080884. Full text in Research Archive Show summary

  Selecting interior wood materials requires balancing functional and aesthetic demands with indoor air quality, as wood can emit volatile organic compounds (VOCs) and very volatile organic compounds (VVOCs) that either peak shortly after installation or persist over time. This study investigated time-resolved VOC and VVOC accumulation concentrations from untreated pine, spruce, aspen, and oak, representing wood species commonly used in Norway. Concentrations of VOCs and VVOCs were monitored for 25–28 days under low-ventilation, worst-case chamber conditions using Proton Transfer Reaction–Time-of-Flight Mass Spectrometry (PTR-TOF-MS). Emission behaviour was assessed using peak concentration, decay rate, half-time, stabilised concentration, cumulative exposure (AUC28), and available health-based thresholds. Clear species-dependent differences were observed. Pine was the dominant VOC source, with the highest peak concentration, stabilised concentration, and AUC28, mainly due to monoterpenes, which remained above the health-based threshold throughout the test period. Oak showed the second-highest VOC burden and a distinct acetate-dominated profile, with acetic acid showing the longest predicted exceedance duration. Aspen and spruce had lower VOC burdens, but their cumulative VVOC exposure exceeded VOC exposure. VVOCs generally peaked earlier than VOCs, although persistence varied by species. Overall, the concentration of VOCs and VVOCs was controlled by species, compound chemistry, volatility, and internal transport, supporting species- and compound-specific ventilation and material-selection strategies.

• Løge, Isaac Appelquist; Kristiansen, Håkon; Shardt, Nadia & Vehus, Tore (2026). Sample holder development for in-situ EBAC mapping of the uniformity of thin-film conductivity. MethodsX. 16. doi: 10.1016/j.mex.2026.103892. Full text in Research Archive Show summary

  Electron beam absorbed current (EBAC) microscopy can provide spatially resolved electrical information that conventional probe methods and local scanning probes often miss in nanoparticulate thin films. Here we present the development of a practical scanning electron microscopy (SEM)-based methodology to qualitatively assess conductivity uniformity and electrical continuity in thin films spanning two electrodes using TiO2 films as a model system. The approach combines a purpose-built insulating holder, readily made without clean-room and advanced lithography access, with embedded electrodes and a measurement configuration to visualize current pathways and identify electrically disconnected regions that may not be apparent from morphology alone. Line scans and 2D maps enable rapid screening of film quality, highlighting cracks, and poor particle connectivity. The workflow is designed for reproducibility and can be adapted to other semiconducting or weakly conducting thin films where microscale continuity is critical to device performance. Fabricate a biasable dual-electrode SEM holder by embedding bent copper plates in an insulating resin body and machining a defined deposition channel (drilled to expose copper + resin in one plane), enabling repeatable electrode gaps and robust external connections for EBAC measurements. Prepare thin films that reliably bridge the electrode gap by using a diluted, well-dispersed nanoparticle suspension (e.g., TiO2 in IPA) and controlled drop-casting into the channel; confirm continuous coverage using standard SEM imaging before electrical mapping. Map conductivity uniformity in situ using EBAC (line scans and 2D maps under applied voltage) to rapidly locate conductive pathways and diagnose electrically disconnected regions that may appear morphologically continuous, providing a reproducible screening workflow adaptable to other weakly conducting thin films.

• Putra, Jouvan Chandra Pratama; Suárez, Silvia; Mateos, Maria Jose; Lao-Zea, Angela; Akhtar, Naureen & Nielsen, Henrik Kofoed [Show all 7 contributors for this article] (2026). TiO<inf>2</inf>/activated-biochar hybrid materials: Weight ratio effects on formaldehyde adsorption and photodegradation. Results in Engineering (RINENG). 30. doi: 10.1016/j.rineng.2026.110337. Full text in Research Archive Show summary

  The performance of Adsorbent-Photocatalyst Hybrids (APHs) based on TiO2 P25 (Evonik) and activated-biochar was investigated for formaldehyde (HCHO) adsorption and photodegradation in the gas phase. Two commercial biochars (birch and Norway spruce) were characterised to identify the most effective adsorbent based on surface area. A microporous wood-based activated charcoal (1374 m2 g-1) served as a reference, with micropore and mesopore volumes of 0.53 and 0.74 cm3 g-1 and pore sizes below 7 nm, for adsorption comparison with the biochars. Subsequently, the selected biochar was activated via wet and dry impregnation methods and then incorporated with TiO2 P25 (Evonik) to form hybrid materials with various weight ratios. The hybrid materials were characterised using BET (surface area), XRF (elemental composition), total carbon analysis, TGA (thermal stability), XRD, and SEM. To evaluate the adsorption and photodegradation performance, a total flow rate of 900 mL min-1 and a HCHO concentration of 15 ppm under UV-A light were applied to the hybrid materials. The results indicated that birch-derived activated biochar with a particle size ≤ 0.5 mm exhibited the highest adsorption performance. When synergised with TiO2 P25 (Evonik) at a 75:25 wt ratio, the hybrid material demonstrated the optimal photodegradation rate and complete mineralisation. The enhanced performance confirms that activated biochar improves photocatalytic efficiency by increasing HCHO availability on the TiO2 P25 (Evonik) surface compared to pure TiO2 P25 (Evonik). These findings provide the optimisation of TiO2-biochar hybrids under high-flow gas-phase conditions and highlight their potential for passive indoor HCHO removal.

• Jabbari, Shahla Ghaffari; Domínguez, Jose Fermoso; Sufuentes, Sandra Rodríguez; Nyberg, Svein Olav Glesaaen; Vehus, Tore & Nielsen, Henrik Kofoed (2025). VOC emissions from commercial wood panels using PTR-MS for indoor air quality evaluation. Frontiers in Built Environment. 11. doi: 10.3389/fbuil.2025.1591669. Full text in Research Archive Show summary

  Introduction: Wood panels, commonly used in cold climates like the Nordic countries for their aesthetic surface and availability, emit volatile organic compounds (VOCs) that can impact indoor air quality and may contribute to health risks, especially with repeated or prolonged exposure. While research has primarily focused on untreated fresh wood, little attention has been given to the VOC emissions from commercial wood panels. This study aims to investigate the VOC emission pattern, intensity, and profile of nine commercially untreated and treated wood panels commonly used in indoor environments, focusing on how wood type and surface treatments influence emission characteristics. Methods: The study utilizes Proton Transfer Reaction Time-of-Flight Mass Spectrometry combined with passive sampling, offering a more comprehensive analysis of volatile organic compounds, including both volatile and very volatile compounds, which traditional gas chromatography cannot capture. Advanced statistical methods, such as Bayesian posterior, principal component analysis, and hierarchical clustering analysis, were employed to identify key emission contributors and classify emission patterns. Results: The findings reveal that emission intensity and profiles are influenced by wood type and surface treatments. Pine and oak emitted higher proportions of VOCs, while spruce primarily emitted VVOCs. Glazing, staining, and painting significantly affect emission intensity, with glazing reducing pine total emissions by 81% and increasing them in spruce by 65%. Staining pine reduced VOC emissions by 74% but increased VVOC emissions by 63%, shifting the emission profile. Despite high emission intensity from untreated pine, painting reduced TVOC emissions by 93%, aligning its profile with lower-emission woods like aspen and spruce, making it more suitable for indoor use. Discussion: The right treatment can transform high-emission woods into materials resembling low-emission species, offering a practical means to mitigate indoor VOC loads.

• 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 Castro, Fernando Gomez & 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. 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. Full text in Research Archive
• 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. 8(2), p. 696–705. doi: 10.1016/j.matpr.2019.02.070. Full text in Research Archive Show summary

  Thermoelectric devices based on oxides are good candidates for energy harvesting technologies for use in aggressive conditions where the materials should withstand high temperatures and corrosive environments over prolonged time. This leads to a natural concern for the stability of the electrical contacts, especially on the hot side of the module. In this work, we have assembled several prototype unicouple thermoelectric modules made by pyrolyzed and spark plasma sintered n-type CaMnO3 and p-type Ca3Co4O9 and then tested under different conditions mimicking end-user applications. For baseline experiments we have chosen to use nickel as the contact material in order to show the effect of its oxidation on performance. In later work we will utilize more oxidation resistant contact materials. A maximum specific power output of 56 mW/cm2 with a temperature difference of 760°C was obtained. Cycling test between 400 to 800°C during a period of 1 week showed a reduction in power output of more than 50% mainly due to crack-formation and oxidation near the nickel/oxide interface

• Silva, Meire Ribeiro da; 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. 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. Full text in Research Archive
• 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 Show summary

  Fluorescence polarization (FP) is a highly regarded technique for studying drug–protein interactions, but has limited value regarding protein mixtures. As a novel approach to drug target discovery, the possibility of combining FP with liquid chromatography (LC) was explored. Nondenaturing protein LC principles such as size-exclusion chromatography (SEC), hydrophobic interaction chromatography (HIC), and ion exchange chromatography (IEX) were found to be orthogonal and compatible with FP because the mobile phases used do not negatively affect detection. For simple protein mixtures, the SEC/HIC/IEX–FP approach was able to identify tankyrase as the target of a triazole-based inhibitor of the Wnt signaling pathway, which is heavily associated with colon cancer. However, the total peak capacity of the three LC dimensions was not sufficient to resolve at cell-proteome level, calling for higher resolution of intact proteins to enable stand-alone drug target discovery with LC and FP.

• 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. 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. Full text in Research Archive
• 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. 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. 2(2). doi: 10.4155/fsoa-2016-0014. Full text in Research Archive
• 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. Full text in Research Archive
• 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. 9(12). doi: 10.1371/journal.pone.0115496. Full text in Research Archive
• 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. 9(9). doi: 10.1371/journal.pone.0106881. Full text in Research Archive Show summary

  A novel open tubular nanoproteomic platform featuring accelerated on-line protein digestion and high-resolution nano liquid chromatography mass spectrometry (LC-MS) has been developed. The platform features very narrow open tubular columns, and is hence particularly suited for limited sample amounts. For enzymatic digestion of proteins, samples are passed through a 20 µm inner diameter (ID) trypsin + endoproteinase Lys-C immobilized open tubular enzyme reactor (OTER). Resulting peptides are subsequently trapped on a monolithic pre-column and transferred on-line to a 10 µm ID porous layer open tubular (PLOT) liquid chromatography LC separation column. Wnt/ß-catenein signaling pathway (Wnt-pathway) proteins of potentially diagnostic value were digested+detected in targeted-MS/MS mode in small cell samples and tumor tissues within 120 minutes. For example, a potential biomarker Axin1 was identifiable in just 10 ng of sample (protein extract of ~1,000 HCT15 colon cancer cells). In comprehensive mode, the current OTER-PLOT set-up could be used to identify approximately 1500 proteins in HCT15 cells using a relatively short digestion+detection cycle (240 minutes), outperforming previously reported on-line digestion/separation systems. The platform is fully automated utilizing common commercial instrumentation and parts, while the reactor and columns are simple to produce and have low carry-over. These initial results point to automated solutions for fast and very sensitive MS based proteomics, especially for samples of limited size.

• 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. Full text in Research Archive Show summary

  Iso-octyl chain-hydroxylated oxysterols were determined in attomoles per 10,000 cells concentrations in 10,000–80,000 cultured pancreatic adenocarcinoma cells, using a sensitive, highly automated nano-LC-ESI-MS-based method. Identified oxysterols included 24S hydroxycholesterol (24S-OHC), 25 hydroxycholesterol (25-OHC), and 27 hydroxycholesterol (27-OHC), while 20S hydroxycholesterol and 22S hydroxycholesterol were not detected. Lower mass limit of quantification was 23 fg (65 amol) for 25-OHC and 27-OHC (100 times lower than our previous method) and 54 fg (135 amol) for 24S-OHC, after derivatization into Girard T hydrazones and online sample cleanup using simplified and robust automatic filtration and filter back flushing solid phase extraction LC/MS/MS. The instrument configuration was easily installed using a commercial nano-LC/MS system. Recoveries in spiked sample were 96, 97, and 77% for 24S-OHC, 25-OHC, and 27-OHC, with within- and between-day repeatabilities of 1–21% and 2–20% relative SD, respectively. The study demonstrates the potential of nano-LC in lipidomics/sterolomics. This research was originally published in the Journal of Lipid Research. Roberg-Larsen H, Lund K, Vehus T, Solberg N, Vesterdal C, Misaghian D, Olsen PA, Krauss S, Wilson SR, Lundanes E.. Highly automated nano-LC/MS-based approach for thousand cell-scale quantification of side chain-hydroxylated oxysterols. J. Lipid Res. 2014 Jul;55(7):1531-6. © the American Society for Biochemistry and Molecular Biology.

• 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. Full text in Research Archive

View all works in NVA

• Vehus, Tore (2025). Indoor Air Quality status and mitigation strategies with use of photocatalysis. Full text in Research Archive Show summary

  Indoor volatile organic compound (VOC) emissions are a worldwide concern, with concentrations indoors often exceeding outdoor levels and contributing significantly to human exposure. The World Health Organization’s Indoor Air Quality Guidelines: Selected Pollutants emphasize that formaldehyde, benzene, and toluene are among the most frequently detected pollutants in homes and workplaces [1]. Large scale monitoring campaigns in Europe and North America confirm that emission rates vary widely depending on surface type, environmental conditions, and occupant activities [2]. A recent UK year long study further demonstrated strong spatial and temporal variability in indoor VOCs, driven by building materials, occupant activities, and ventilation practices [3]. Collectively, these findings underscore that indoor VOCs are persistent and highly context dependent, making source control and mitigation strategies a public health priority. Wood is valued in buildings for its warmth and sustainability, but its VOC emissions—shaped by species, manufacturing, and surface treatments—can strongly affect indoor air quality. High resolution studies using PTR ToF MS show how different panels and finishes alter emission profiles, with direct implications for material choice [4]. Photocatalysis offers a complementary route for VOC mitigation [5]. From light driven pathways to emerging insights on charge carrier dynamics under low illumination, recent work clarifies both the potential and the limits of photocatalytic air purification, with incorporation of biocarbon into TiO2. [1] World Health Organization. (2010). WHO guidelines for indoor air quality: Selected pollutants. WHO Regional Office for Europe. [2] European Environment Agency. (2020). Indoor air quality and health. Publications Office of the European Union. [3] Jones, P., Smith, R., & Taylor, L. (2024). Long‑term monitoring of indoor VOC emissions in UK dwellings. Science of the Total Environment, 889, 164–175. [4] Ghaffari Jabbari, S., Fermoso Domínguez, J., Rodríguez Sufuentes, S., Nyberg, S. O., Sandnes Vehus, T., & Kofoed Nielsen, H. (2025). VOC emissions from commercial wood panels using PTR-MS for indoor air quality evaluation. Frontiers in Built Environment, 11, 1591669. [5] Putra et.al Photocatalysis of formaldehyde with TiO2 and biochar composite (Manuscript in preparation)

• Nielsen, Henrik Kofoed & Vehus, Tore (2025). Focusing on the use of wood as a building material in relation to IAQ and human health. [Internet]. https://www.youtube.com/watch?v=NoaBkOFqflk&t=1s. Full text in Research Archive
• Jabbari, Shahla Ghaffari; Nielsen, Henrik Kofoed & Vehus, Tore (2024). EXPLORING THE EFFECTIVENESS OF DIFFERENT AIR CLEANER TECHNOLOGIES IN REMOVING AIR POLLUTANTS WITH FOCUSING ON ENERGY SAVING and COSTS - AN OVERVIEW. Full text in Research Archive
• Putra, Jouvan Chandra Pratama; Vehus, Tore & Nielsen, Henrik Kofoed (2023). A Review on Electron-Hole Pairs Mechanism in Dark Photocatalysis. Full text in Research Archive
• 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. Full text in Research Archive
• Brandtzaeg, Ole Kristian; Levernæs, Maren Christin Stillesby; Halvorsen, Trine Grønhaug; Reubsaet, Leon; Røen, Bent Tore & Vehus, Tore [Show all 10 contributors for this article] (2018). Online sample processing systems for targeted nano liquid chromatography mass spectrometry bioanalysis. Full text in Research Archive
• 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. Full text in Research Archive 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.

• Vehus, Tore; Skomedal, Gunstein; Kanas, Nikola & Middleton, Peter Hugh (2018). Hot side electrical contacts for oxide thermoelectric modules. Full text in Research Archive
• Vehus, Tore & Surup, Gerrit Ralf (2018). Investigation of bio-oil from high-temperature pyrolysis of spruce. Full text in Research Archive
• 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. Full text in Research Archive 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.

• 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. Full text in Research Archive
• Wilson, Steven Ray Haakon; Vehus, Tore; Røberg-Larsen, Hanne & Lundanes, Elsa (2016). “Sub-chip” liquid chromatography-mass spectrometry for measuring oxysterols and related proteins. Full text in Research Archive
• 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. Full text in Research Archive
• Surup, Gerrit; Nielsen, Henrik Kofoed; Vehus, Tore & Eidem, Per Anders (2016). Biochar from medium pyrolysis temperatures for smelting plant applications. Full text in Research Archive
• Smetop, Tone; Vehus, Tore; Wilson, Steven Ray Haakon & Lundanes, Elsa (2016). Silica-based monolithic pre-columns in miniaturized liquid chromatography. Full text in Research Archive
• Berg, Henriette Sjånes; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Optimization of in-house packed nano-LC columns for peptide separations. Full text in Research Archive
• Vehus, Tore (2016). Utvikling og bruk av ny C18 funksjonalisert silika i porøse opne røyrkolonner (PLOT). Full text in Research Archive
• 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. Full text in Research Archive
• 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. Full text in Research Archive
• 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. 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] (2016). Capillary LC mass spectrometric detection of 27-hydroxycholesterol in breast cancer exosomes. Full text in Research Archive
• 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. Full text in Research Archive 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.

• 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. Full text in Research Archive
• 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. Full text in Research Archive
• 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. Full text in Research Archive
• Vehus, Tore; Greibrokk, Tyge; Lundanes, Elsa & Wilson, Steven Ray Haakon (2014). Proteomic Analysis of the Wnt/beta-catenin Pathway. Full text in Research Archive
• 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. Full text in Research Archive
• 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. Full text in Research Archive
• Vehus, Tore (2007). Performing Quantitative Determination of Low-Abundant Proteins by Targeted Mass Spectrometry Liquid Chromatography. In Aliofkhazraei, Mahmood (Eds.), Mass spectrometry. IntechOpen. ISSN 9789535132240. p. 79–94. doi: 10.5772/intechopen.68713. Full text in Research Archive
• 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. Full text in Research Archive
• Hassine, Esma Ben; 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. Universitetet i Oslo. Full text in Research Archive 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.

• 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. Full text in Research Archive 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. Full text in Research Archive 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. Full text in Research Archive 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. Full text in Research Archive 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. Full text in Research Archive 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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