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12. Monitoring Drug Pharmacokinetics

Author

Haick, Hossam, Haick, H ( Hossam ), Schmidt, F, Osswald, M, Zenobi, R, Kohler, M, Haick, Hossam, Haick, H ( Hossam ), Schmidt, F, Osswald, M, Zenobi, R, and Kohler, M

Abstract

Monitoring of drug pharmacokinetics is used in personalized therapy, therapeutic drug monitoring (TDM), toxicology assessments, doping controls and clinical drug development. Drugs are predominantly measured in plasma, serum or urine. Monitoring of volatile organic compounds (VOCs) in breath has so far not received much attention, but nevertheless it has many advantages over conventional approaches. This chapter presents the principles of basic pharmacokinetics, focusing on volatiles and related physiological concepts. It also offers a comprehensive overview of drugs detected in exhaled breath. Finally, it also presents the necessary analytical and sensing tools to monitor volatile organic drugs, with selected pharmaceutical examples by which their potential is discussed.

Published
2022

13. Ion mobility spectrometry coupled to laser-induced fluorescence for probing the electronic structure and conformation of gas-phase ions

Author

Frankevich, V.E., Barylyuk, K.V., Sinues, P. Martinez-Lozano, and Zenobi, R.

Subjects
Analysis, Ionization -- Analysis, Fluorescence -- Investigations -- Analysis
Abstract

INTRODUCTION Laser-induced fluorescence (LIF) analyzers are based on measurements of fluorescence spectra induced in a test sample irradiated with a laser. The measured spectrum represents a set fluorescence signals from [...], We report on an improved design of a differential ion mobility analyzer (DMA) coupled to laser-induced fluorescence (LIF) for the simultaneous retrieval of two-dimensional information on the electric mobility and fluorescence spectroscopy of gas-phase ions. This enhanced design includes an ion funnel interface at the input orifice of the DMA and a nozzle beam stage at the output of the DMA. These improvements allow the detection of fluorescence not only from pure dyes and their clusters, as was demonstrated recently, but also from fluorophore-tagged biomolecules. Complex mixtures of fluorescent compounds can be separated by the DMA and studied by LIF. This unique combination of instruments also provides a powerful platform for probing fluorescent proteins in the gas phase. The green fluorescent protein (GFP) was tested on a new setup. In contrast to high vacuum, where no GFP fluorescence was detected, the presence of a LIF signal at the output of the DMA could explain some specific fluorescent properties of GFP in the gas phase. Given that both conformation and fluorescence are key properties of biological molecules in the gas phase, we expect that our enhanced design will answer the question whether gas-phase proteins retain their liquid-phase native structure or not. Keywords: differential ion mobility analyzer, laser-induced fluorescence, green fluorescent protein, electrospray, gas-phase ions, soft ionization, native proteins DOI: 10.1134/S106193481413005X

Published
2014
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16. The peppermint breath test : A benchmarking protocol for breath sampling and analysis using GC-MS

Author

Wilkinson, M., White, I., Hamshere, K., Holz, O., Schuchardt, S., Bellagambi, F.G., Lomonaco, T., Biagini, D., Di, Francesco F., Fowler, S.J., Beauchamp, J.D., Cristescu, S.M., Focant, J.F., Franchina, F.A., Grassin-Delyle, S., Hadjithekli, A., Henderson, B., Koppen, G.F., Langejürgen, J., Malásková, M., Mayhew, C., Moreno, S., Pedrotti, M., Pugliese, G., Ruszkiewicz, D.M., Salman, D., Sinues, P., Slingers, G.F., Stefanuto, P.H., Thomas, C.L.P., Wilde, M., Zanella, D., and Zenobi, R.

Subjects
Pulmonary and Respiratory Medicine, Benchmarking, Breathomics, Peppermint, Standardisation, Breath Tests, Exhalation, Gas Chromatography-Mass Spectrometry, Humans, Mentha piperita, Volatile Organic Compounds, standardisation, breathomics, peppermint, benchmarking, NO, chemistry.chemical_compound, standardisation, breathomics, peppermint, benchmarking, medicine, VLAG, Protocol (science), Baseline values, Breath test, Chromatography, medicine.diagnostic_test, Breath sampling, Menthone, Eucalyptol, Food Quality and Design, chemistry, Environmental science, Post Harvest Technology, Gas chromatography–mass spectrometry, Menthol
Abstract

Exhaled breath contains hundreds of volatile organic compounds (VOCs) which offer the potential for diagnosing and monitoring a wide range of diseases. As the breath research field has grown, sampling and analytical practices have become highly varied between groups. Standardisation would allow meta-analyses of data from multiple studies and greater confidence in published results. Washout of VOCs from ingestion into the blood and subsequently breath could provide data for an initial assessment of inter-group performance. The Peppermint Initiative has been formed to address this task of standardisation. In the current study we aimed to generate initial benchmark values for thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) analysis of breath samples containing peppermint-derived VOCs using data from three independent European research groups. Initially, headspace analysis of peppermint oil capsules was performed to determine compounds of interest. Ten healthy participants were recruited by each three groups across Europe. The standard Peppermint protocol was followed. In brief, each participant provided a baseline breath sample prior to taking a peppermint capsule, with further samples collected at 60, 90, 165, 285 and 360 min following ingestion. Sampling and analytical protocols were different for each group, in line with their usual practice. Samples were analysed by TD–GC–MS and benchmarking values determined for the time taken for detected peppermint VOCs to return to baseline values. Sixteen compounds were identified in the capsule headspace, and all were confirmed in breath following ingestion of the peppermint capsules. Additionally, 2,3-dehydro-1,8-cineole was uniquely found in the breath samples, with a washout profile that suggested it was a product of metabolism of peppermint compounds. Five compounds (α-pinene, β-pinene, eucalyptol, menthol and menthone) were quantified by all three groups. Differences were observed between the groups, particularly for the recovery of menthone and menthol. The average time taken for VOCs to return to baseline was selected as the benchmark and were 377, 423, 533, 418 and 336 min for α-pinene, β-pinene, eucalyptol, menthone and menthol respectively. We have presented an initial set of easy-to-measure benchmarking values for assessing the performance of TD–GC–MS systems for the analysis of VOCs in breath. These values will be updated when more groups provide additional data., Journal of Breath Research, 15 (2), ISSN:1752-7155, ISSN:1752-7163

Published
2021
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19. Quantitative analysis of polycyclic aromatic hydrocarbons in water in the low-nanogram per liter range with two-step laser mass spectrometry

Author

Emmenegger, C., Kalberer, M., Morrical, B., and Zenobi, R.

Subjects
Polycyclic aromatic hydrocarbons -- Research, Chemistry
Abstract

Polycyclic aromatic hydrocarbons (PAHs) are of major concern in all environmental compartments due to the mutagenic and carcinogenic properties of many PAHs. Two-step laser mass spectrometry (L2MS) is a sensitive and selective method to measure PAHs in complex solid matrixes. However, in most studies, L2MS was used for qualitative or semiquantitative analyses. Here we present for the first time a quantitative method analyzing PAl-Is in water at the nanogram per liter level. PAHs are extracted from a 30-mL water sample with a solid PVC membrane, which is then directly measured by L2MS without further treatment. Detection limits are in the low-nanogram per liter range (2-125 ng/L) for skeletal three-to six-ring PAHs. Extraction efficiencies of this method are between 75 and 90%. In a first application, samples from a wastewater treatment plant were measured, showing that microbial activities efficiently decrease PAH concentrations by 75-90%.

Published
2003

21. Picogram quantitation of polycyclic aromatic hydrocarbons adsorbed on aerosol particles by two-step laser mass spectrometry

Author

Kalberer, M., Morrical, B.D., Sax, M., and Zenobi, R.

Subjects
Chemistry, Analytic -- Research, Polycyclic aromatic hydrocarbons -- Analysis, Mass spectrometry -- Usage, Chemistry
Abstract

Polycyclic aromatic hydrocarbons (PAHs) are emitted into the atmosphere mostly by anthropogenic combustion sources. Because of their carcinogenic and mutagenic properties, PAHs are often analyzed in air quality measurements. Atmospheric concentrations of PAHs, typically in the nanograms-per-cubic-meter range, require significant effort for sample collection and processing when conventional methods such as gas chromatography/mass spectrometry (GC/MS) or liquid chromatography/mass spectrometry are used. In contrast, two-step laser mass spectrometry (L2MS) is highly sensitive and selective for PAils and requires almost no sample preparation. Here, we present for the first time a method based on L2MS to quantify PAlls adsorbed on aerosol particles collected on a filter. Linear ranges for quantitation were determined for five different PAHs in the mass range of 178-276 Da (i.e., phenanthrene, pyrene, chrysene, benzo[e]pyrene, benzo[ghi]perylene) covering more than 2 orders of magnitude with detection limits between 50 and 300 pg of a single PAH on a whole filter sample. A quantitative comparison with GC/MS was performed using model aerosols consisting of benzo[e]pyrene adsorbed on inorganic salt aerosol particles. On average, 25% less benzo[e]pyrene was determined with GC/MS than with L2MS, with a variability between the two methods of [+ or -] 68%. The general lower amount measured with GC/MS is attributed to losses during the sample preparation for the GC/MS measurements.

Published
2002

23. YnaI

Author

Flegler, V.J., primary, Rasmussen, A., additional, Rao, S., additional, Wu, N., additional, Zenobi, R., additional, Sansom, M.S.P., additional, Hedrich, R., additional, Rasmussen, T., additional, and Boettcher, B., additional

Published
2020
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24. YnaI in an open-like conformation

Author

Flegler, V.J., primary, Rasmussen, A., additional, Rao, S., additional, Wu, N., additional, Zenobi, R., additional, Sansom, M.S.P., additional, Hedrich, R., additional, Rasmussen, T., additional, and Boettcher, B., additional

Published
2020
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25. small conductance mechanosensitive channel YbiO

Author

Flegler, V.J., primary, Rasmussen, A., additional, Rao, S., additional, Wu, N., additional, Zenobi, R., additional, Sansom, M.S.P., additional, Hedrich, R., additional, Rasmussen, T., additional, and Boettcher, B., additional

Published
2020
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28. Abstracts of the 6th FECS Conference 1998 Lectures

Author

Rowland, F. Sherwood, Blake, Donald R., Larsen, B. R., Lindskog, Anne, Peterson, Peter J., Williams, W. Peter, Wallington, T. J., Pilling, M. J., Carslaw, N., Creasey, D. J., Heard, D. E., Jacobs, P., Lee, J., Lewis, A. C., McQuaid, J. B., Stockwell, William R., Frank, Hartmut, Sacco, P., Cocheo, V., Lynge, E., Andersen, A., Nilsson, R., Barlow, L., Pukkala, E., Nordlinder, R., Boffetta, P., Grandjean, P., Heikkil, P., Hürte, L. G., Jakobsson, R., Lundberg, I., Moen, B., Partanen, T., Riise, T., Borowiak, A., De Saeger, E., Schnitzler, K. G., Gravenhorst, G., Jacobi, H. W., Moelders, S., Lammel, G., Busch, G., Beese, F. O., Dentener, F. J., Feichter, J., Fraedrich, K., Roelofs, G. J., Friedrich, R., Reis, S., Voehringer, F., Simpson, D., Moussiopoulos, N., Sahm, P., Tourlou, P. M., Salmons, R., Papameletiou, D., Maqueda, J. M., Suhr, Per B., Bell, W., Paton-Walsh, C., Woods, P. T., Partridge, R. H., Slemr, J., Slemr, F., Schmidbauer, N., Ravishankara, A. R., Jenkin, Michael E., de Leeuw, G., van Eijk, A. M. J., Flossmann, A. I., Wobrock, W., Mestayer, P. G., Tranchant, B., Ljungström, E., Karlsson, R., Larsen, S. E., Roemer, M., Builtjes, P. J. H., Koffi, Brigitte, Koffi, Ernest N’Dri, De Saeger, Emile, Ro-Poulsen, H., Mikkelsen, T. N., Hummelshøj, P., Hovmand, M. F., Simoneit, Bernd R. T., van der Meulen, A., Meyer, Michael B., Berndt, T., Böge, O., Stratmann, F., Cass, Glen R., Harrison, Roy M., Shi, Ji Ping, Hoffmann, T., Warscheid, B., Bandur, R., Marggraf, U., Nigge, W., Kamens, Richard, Jang, Myoseon, Strommen, Mike, Chien, Chao-Jung, Leach, Keri, Ammann, M., Kalberer, M., Arens, F., Lavanchy, V., Gâggeler, H. W., Baltensperger, U., Davies, J. A., Cox, R. A., Alonso, S. García, Pastor, R. Pérez, Argüello, Gustavo A., Willner, Helge, Berndt, T., Böge, O., Bogillo, V. I., Pokrovskiy, V. A., Kuraev, O. V., Gozhyk, P. F., Bolzacchini, E., Bruschi, M., Fantucci, P., Meinardi, S., Orlandi, M., Rindone, B., Bolzacchini, Ezio, Bohn, Birger, Rindone, Bruno, Bruschi, Maurizo, Zetzsch, Cornelius, Brussol, C., Duane, M., Larsen, B., Carlier, P., Kotzias, D., Caracena, A. Baeza, Aznar, A. Miñana, Ferradás, E. González, Christensen, C. S., Skov, H., Hummelshøj, P., Jensen, N. O., Lohse, C., Cocheo, V., Sacco, P., Chatzis, C., Cocheo, V., Sacco, P., Boaretto, C., Quaglio, F., Zaratin, L., Pagani, D., Cocheo, L., Cocheo, Vincenzo, Asnar, Agustin Minana, Baldan, Annerita, Ballesta, Pascual P., Boaretto, Caterina, Caracena, Antonia B., Ferradas, Enrique Gonzalez, Gonzalez-Flesca, Nobert, Goelen, Eddie, Hansen, Asger B., Sacco, Paolo, De Saeger, Emile, Skov, Henrik, Consonni, V., Gramatica, P., Santagostino, A., Galvani, P., Bolzacchini, E., Consonni, Viviana, Gramatica, Paola, Todeschini, Roberto, Dippel, G., Reinhardt, H., Zellner, R., Dämmer, K., Bednarek, G., Breil, M., Zellner, R., Febo, A., Allegrini, I., Giliberti, C., Perrino, C., Fogg, P. G. T., Geiger, H., Barnes, I., Becker, K. H., Maurer, T., Geyskens, F., Bormans, R., Lambrechts, M., Goelen, E., Giese, Martina, Frank, Hartmut, Glasius, M., Hornung, P., Jacobsen, J. K., Klausen, H. S., Klitgaard, K. C., Møller, C. K., Petersen, A. P. F., Petersen, L. S., Wessel, S., Hansen, T. S., Lohse, C., Boaretto, E., Heinemeier, J., Glasius, M., Di Bella, D., Lahaniati, M., Calogirou, A., Jensen, N. R., Hjorth, J., Kotzias, D., Larsen, B. R., Gonzalez-Flesca, N., Cicolella, A., Bates, M., Bastin, E., Gurbanov, M. A., Akhmedly, K. M., Balayev, V. S., Haselmann, K. F., Ketola, R., Laturnus, F., Lauritsen, F. R., Grøn, C., Herrmann, H., Ervens, B., Reese, A., Umschlag, Th., Wicktor, F., Zellner, R., Herrmann, H., Umschlag, Th., Müller, K., Bolzacchini, E., Meinardi, S., Rindone, B., Jenkin, Michael E., Hayman, Garry D., Jensen, N. O., Courtney, M., Hummelshøj, P., Christensen, C. S., Larsen, B. R., Johnson, Matthew S., Hegelund, Flemming, Nelander, Bengt, Kirchner, Frank, Klotz, B., Barnes, Ian, Sørensen, S., Becker, K. H., Etzkorn, T., Platt, U., Wirtz, K., Martín-Reviejo, M., Laturnus, Frank, Martinez, E., Cabañas, B., Aranda, A., Martín, P., Salgado, S., Rodriguez, D., Masclet, P., Jaffrezo, J. L., Hillamo, R., Mellouki, A., Le Calvé, S., Le Bras, G., Moriarty, J., O’Donnell, S., Wenger, J., Sidebottom, H., Mingarrol, M. T. Bomboi, Cosin, S., Pastor, R. Pérez, Alonso, S. García, Sanz, M. J., Bravo, I., Gonzalez, D., Pérez, M. A., Mustafaev, Islam, Mammadova, Saida, Noda, J., Hallquist, M., Langer, S., Ljungström, E., Nohara, K., Kutsuna, S., Ibusuki, T., Oehme, Michael, Kölliker, Stephan, Brombacher, Stephan, Merz, Leo, Pastor, R. Pérez, Alonso, S. García, Cabezas, A. Quejido, Peeters, J., Vereecken, L., El Yazal, J., Pfeffer, Hans-Ulrich, Breuer, Ludger, Platz, J., Nielsen, O. J., Sehested, J., Wallington, T. J., Ball, J. C., Hurley, M. D., Straccia, A. M., Schneider, W. F., Pérez-Casany, M. P., Nebot-Gil, I., Sánchez-Marín, J., Putz, E., Folberth, G., Pfister, G., Weissflog, L., Elansky, N. P., Sørensen, Søren, Barnes, Ian, Becker, K. H., Shao, M., Heiden, A. C., Kley, D., Rockel, P., Wildt, J., Silva, G. V. A., Vasconcelos, M. T., Fernandes, E. O., Santos, A. M. S., Skov, Henrik, Hansen, Asger, Løfstrøm, Per, Lorenzen, Gitte, Stabel, J. R., Wolkoff, P., Pedersen, T., Strom, A. B., Skov, Henrik, Hertel, Ole, Jensen, Finn Palmgren, Hjorth, Jens, Galle, Bosse, Wallin, Svante, Theloke, J., Libuda, H. G., Zabel, F., Touaty, Muriel, Bonsang, Bernard, Ullerstam, M., Langer, S., Ljungström, E., Wenger, John, Bonard, Amélie, Manning, Marcus, Nolan, Sinéad, O’Sullivan, Niamh, Sidebottom, Howard, Wenger, John, Collins, Eoin, Moriarty, Jennie, O’Donnell, Sinéad, Sidebottom, Howard, Wenger, John, Collins, Eoin, Moriarty, Jennie, O’Donnell, Sinéad, Sidebottom, Howard, Wenger, John, Sidebottom, Howard, Chadwick, Paul, O’Leary, Barbara, Treacy, Jack, Wolkoff, Peder, Clausen, Per A., Wilkins, Cornelius K., Hougaard, Karin S., Nielsen, Gunnar D., Zilinskis, Viktors, Jansons, Guntis, Peksens, Aigars, Lazdins, Agris, Arinci, Y. V., Erdöl, N., Ekinci, E., Okutan, H., Manlafalioglu, I., Bakeas, Evangelos B., Siskos, Panayotis A., Viras, Loizos G., Smirnioudi, Vasiliki N., Bottenheim, Jan W., Biesenthal, Thomas, Gong, Wanmin, Makar, Paul, Delmas, Véronique, Menard, Tamara, Tatry, Véronique, Moussafir, Jacques, Thomas, Dominique, Coppalle, Alexis, Ellermann, Thomas, Hertel, Ole, Skov, Henrik, Frohn, Lise, Manscher, Ole H., Friis, Jørgen, Girgzdiene, Rasa, Girgzdys, Aloyzas, Gurevich, N. A., Gårdfeldt, Katarina, Langer, Sarka, Hermans, C., Vandaele, A. C., Carleer, M., Fally, S., Colin, R., Bernath, P. F., Jenouvrier, A., Coquart, B., Mérienne, M. -F., Hertel, Ole, Frohn, Lise, Skov, Henrik, Ellermann, Thomas, Huntrieser, H., Schlager, H., Feigl, C., Kemp, Kåre, Palmgren, Finn, Kiilsholm, Sissi, Rasmussen, Alix, Sørensen, Jens Havskov, Klemm, Otto, Lange, Holger, Larsen, René Wugt, Larsen, Niels Wessel, Nicolaisen, Flemming, Sørensen, Georg Ole, Beukes, Jon Are, Larsen, Poul Bo, Jensen, Steen Solvang, Fenger, Jes, de Leeuw, Gerrit, Kunz, Gerard, Cohen, Leo, Schlünzen, Heinke, Muller, Frank, Schulz, Michael, Tamm, Susanne, Geernaert, Gary, Hertel, Ole, Pedersen, Britta, Geernaert, Lise Lotte Sørensen, Lund, Søren, Vignati, Elisabetta, Jickells, Tim, Spokes, Lucinda, Matei, C., Jinga, O. A., Jinga, D. C., Moliner, R., Braekman-Danheux, C., Fontana, A., Suelves, I., Thieman, T., Vassilev, S., Skov, Henrik, Hertel, Ole, Zlatev, Zahari, Brandt, Jørgen, Bastrup-Birk, Annemarie, Ellermann, Thomas, Frohn, Lise, Vandaele, A. C., Hermans, C., Carleer, M., Tsouli, A., Colin, R., Windsperger, Andreas M., Turi, Kristina, Dworak, Oliver, Zellweger, C., Weingartner, E., Rüttimann, R., Hofer, P., Baltensperger, U., Ziv, A., Iakovleva, E., Palmgren, F., Berkovicz, R., Skov, H., Alastuey, A., Querol, X., Chaves, A., Lopez-Soler, A., Ruiz, C., Andrees, J. M., Allegrini, I., Febo, A., Giusto, M., Angeloni, M., Di Filippo, P., D’Innocenzio, F., Lepore, L., Marconi, A., Arshinov, M. Yu., Belan, B. D., Davydov, D. K., Kovaleskii, V. K., Plotinov, A. P., Pokrovskii, E. V., Sklyadneva, T. K., Tolmachev, G. N., Arshinov, M. Yu., Belan, B. D., Sklyadneva, T. K., Behnke, Wolfgang, Elend, Manfred, Krüger, Ulrich, Zetzsch, Cornelius, Belan, B. D., Arshinov, M. Yu., Davydov, D. K., Kovalevskii, V. K., Plotnikov, A. P., Pokrovskii, E. V., Rasskazchikova, T. M., Sklyadneva, T. K., Tolmachev, G. N., Belan, B. D., Arshinov, M. Yu., Simonenkov, D. V., Tolmachev, G. N., Bilde, Merete, Aker, Pamela M., Börensen, C., Kirchner, U., Scheer, V., Vogt, R., Ellermann, T., Geernaert, L. L. S., Pryor, S. C., Barthelmie, R. J., Feilberg, Anders, Nielsen, Torben, Kamens, Richard M., Freitas, M. C., Marques, A. P., Reis, M. A., Alves, L. C., Ilyinskikh, N. N., Ilyinskikh, I. N., Ilyinskikh, E. N., Johansen, Keld, Stavnsbjerg, Peter, Gabrielsson, Pär, Bak, Flemming, Andersen, Erik, Autrup, Herman, Kamens, Richard, Jang, Myoseon, Strommen, Michael, Leach, Keri, Kirchner, U., Scheer, V., Börensen, C., Vogt, R., Igor, Komov, Svjatoslav, Galiy, Anatoliy, Burlak, Komov, I. L., Istchenko, A. A., Lourenço, M. G., MacTavish, D., Sirois, A., Masclet, Pierre, Jaffrezo, Jean Luc, van der Meulen, A., Milukaite, A., Morkunas, V., Jurgutis, P., Mikelinskiene, A., Nielsen, Torben, Feilberg, Anders, Binderup, Mona Lise, Pineda, M., Palacios, J. M., Garcia, E., Cilleruelo, C., Moliner, R., Popovitcheva, O. B., Trukhin, M. E., Persiantseva, N. M., Buriko, Yu, Starik, A. M., Demirdjian, B., Suzanne, J., Probst, T. U., Rietz, B., Alfassi, Z. B., Pokrovskiy, V. A., Zenobi, R., Bogatyr’ov, V. M., Gun’ko, V. M., Querol, X., Alastuey, A., Lopez-Soler, A., Mantilla, E., Plana, F., Artiño, B., Rauterberg-Wulff, A., Israël, G. W., Rocha, Teresa A. P., Duarte, Armando C., Röhrl, Andreas, Lammel, Gerhard, Spindler, G., Müller, K., Herrmann, H., Strommen, Michael R., Vignati, Elisabetta, de Leeuw, Gerrit, and Berkowicz, Ruwim

Published
1998
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36. Ion mobility spectrometry coupled to laser-induced fluorescence for probing the electronic structure and conformation of gas-phase ions

Author

Frankevich, V., Barylyuk, K., Martinez-Lozano Sinues, P., Zenobi, R., Frankevich, V., Barylyuk, K., Martinez-Lozano Sinues, P., and Zenobi, R.

Abstract

We report on an improved design of a differential ion mobility analyzer (DMA) coupled to laser-induced fluorescence (LIF) for the simultaneous retrieval of two-dimensional information on the electric mobility and fluorescence spectroscopy of gas-phase ions. This enhanced design includes an ion funnel inter-face at the input orifice of the DMA and a nozzle beam stage at the output of the DMA. These improvements allow the detection of fluorescence not only from pure dyes and their clusters, as was demonstrated recently, but also from fluorophore-tagged biomolecules. Complex mixtures of fluorescent compounds can be separated by the DMA and studied by LIF. This unique combination of instruments also provides a powerful platform for probing fluorescent proteins in the gas phase. The green fluorescent protein (GFP) was tested on a new setup. In contrast to high vacuum, where no GFP fluorescence was detected, the presence of a LIF signal at the output of the DMA could explain some specific fluorescent properties of GFP in the gas phase. Given that both conformation and fluorescence are key properties of biological molecules in the gas phase, we expect that our enhanced design will answer the question whether gas-phase proteins retain their liquid-phase native structure or not.

Published
2019

39. Photochemical creation of covalent organic 2D monolayer objects in defined shapes via a lithographic 2D-polymerization

Author

Servalli, M., Celebi, K., Payamyar, P., Zheng, L., Polozij, M., Lowe∥, B., Kuc, A., Schwarz, T., Thorwarth, K., Borgschulte○, A., Heine, T., Zenobi, R., and Schlüter, A. D.

Abstract

In this work, we prepare Langmuir-Blodgett monolayers with a trifunctional amphiphilic anthraphane monomer. Upon spreading at the air/water interface, the monomers self-assemble into 1 nm-thin monolayer islands, which are highly fluorescent and can be visualized by naked eye upon excitation. In-situ fluorescence spectroscopy indicates that in the monolayers, all the anthracene units of the monomers are stacked face-to-face forming excimer pairs, whereas at the edges of the monolayers free anthracenes are present acting as edge groups. Irradiation of the monolayer triggers [4+4]-cycloadditions among the excimer pairs, effectively resulting in a two-dimensional polymerization. The polymerization reaction also completely quenches the fluorescence, allowing to draw patterns on the monomer monolayers. More interestingly, after transferring the monomer monolayer on a solid substrate, by employing masks or the laser of a confo-cal scanning microscope, it is possible to arbitrarily select the parts of the monolayer that one wants to polymerize. The unpolymerized regions can then be washed away from the substrate, leaving two-dimensional macromolecular monolayer objects of the desired shape. This is the first photolithographic process that employs 2D-polymerizations and affords 1 nm-thin coatings.

Published
2018

42. Characterization of aerosol plumes in nanosecond laser ablation of molecular solids at atmospheric pressure

Author

Schmitz, T., Koch, J., Günther, D., Zenobi, R., Schmitz, T., Koch, J., Günther, D., and Zenobi, R.

Abstract

Ablation of molecular solids with pulsed ultraviolet lasers at atmospheric pressure is an important process in (bio-)organic mass spectrometry. Of practical importance for analytical sampling and analysis are the plume formation and expansion. Plumes formed by atmospheric-pressure laser ablation of anthracene and 2,5-dihydroxybenzoic acid (2,5-DHB) were studied by light scattering imaging, which showed significant material release in the form of aerosols. The monitored plume expansion dynamics could be fitted to the drag-force model, yielding initial plume velocities of 150m/s for anthracene and 43m/s for DHB. While the angle of incidence does not affect the plume direction and propagation, a large dependence of the plume-expansion velocity on the laser pulse energy could be found, which is limited at atmospheric pressure by the onset of plasma shielding. With respect to analytical applications, the efficiency of sampling of the laser ablation products by a capillary could be experimentally visualized

Published
2018

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