Wolfgang Vautz

Leibniz-Institut für Analytische Wissenschaften, Dortmund, North Rhine-Westphalia, Germany

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Publications (65)77.2 Total impact

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    ABSTRACT: The design, development, and validation of a dynamic vapor generator are presented. The generator simulates human scent (odor) emissions from trapped victims in the voids of collapsed buildings. The validation of the device was carried out using a reference detector: a quadrupole mass spectrometer equipped with a pulsed sampling (PS-MS) system. A series of experiments were conducted for evaluating the simulator's performance, defining types and weights of different factors, and proposing further optimization of the device. The developed device enabled the production of stable and transient odor profiles in a controllable and reproducible way (relative standard deviation, RSD < 11%) at ppbv to low ppmv concentrations and allowed emission durations up to 30 min. Moreover, the factors affecting its optimum performance (i.e., evaporation chamber temperature, air flow rate through the mixing chamber, air flow rate through the evaporation chamber, and type of compound) were evaluated through an analysis of variance (ANOVA) tool revealing the next steps toward optimizing the generator. The developed simulator, potentially, can also serve the need for calibrating and evaluating the performance of analytical devices (e.g., gas chromatographers, ion mobility spectrometers, mass spectrometers, sensors, e-noses) in the field. Furthermore, it can contribute in better training of urban search and rescue (USaR) canines.
    Analytical Chemistry 04/2014; · 5.82 Impact Factor
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    ABSTRACT: Ion mobility spectrometry (IMS) is a well-known analytical method for the detection of CWAs and explosives since many years. Coupling IMS to GC pre-separation, new application fields in medicine and biology could be opened, dealing with complex and humid mixtures. However, identification of unknowns in such a complex sample is challenging and can only be achieved by parallel GC/MS analysis, thus obtaining a proposal for the responsible compound for validation via reference substances by GC/IMS again. The available adsorption tools for such accompanying GC/MS analysis have their particular drawbacks (e.g. problematic quantification for SPME, high sample volumes for adsorption tubes). Therefore miniaturised adsorption needles (NeedleTrap) were applied to both GC/IMS and GC/MS for validation of their reproducibility. It could be demonstrated that the needles can even be used for appropriate quantification when the adsorbent and the sample volume are adapted properly to the concentration range, the compounds of interest and humidity of the sample. The method is very flexible with regard to the concentration range by variation of the sample volume (e.g. 20 mL for pptV, 10 mL for lower ppbV or 1 mL for ppmV) and with regard to the compounds of interest by application of common adsorption materials optimised for the relevant substance group. Such materials are available commercially in a broad variability. Therefore, the miniaturised adsorption needles are a helpful complementary sampling method for any GC/MS or GC/IMS investigations.
    International Journal for Ion Mobility Spectrometry 03/2014; 17(1).
  • 17th INTERPOL International Forensic Science Managers Symposium, Lyon, France; 10/2013
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    ABSTRACT: For the comprehensive simulation of ion trajectories including reactive collisions at elevated pressure conditions, a chemical reaction simulation (RS) extension to the popular SIMION software package was developed, which is based on the Monte Carlo statistical approach. The RS extension is of particular interest to SIMION users who wish to simulate ion trajectories in collision dominated environments such as atmospheric pressure ion sources, ion guides (e.g., funnels, transfer multi poles), chemical reaction chambers (e.g., proton transfer tubes), and/or ion mobility analyzers. It is well known that ion molecule reaction rate constants frequently reach or exceed the collision limit obtained from kinetic gas theory. Thus with a typical dwell time of ions within the above mentioned devices in the ms range, chemical transformation reactions are likely to occur. In other words, individual ions change critical parameters such as mass, mobility, and chemical reactivity en passage to the analyzer, which naturally strongly affects their trajectories. The RS method simulates elementary reaction events of individual ions reflecting the behavior of a large ensemble by a representative set of simulated reacting particles. The simulation of the proton bound water cluster reactant ion peak (RIP) in ion mobility spectrometry (IMS) was chosen as a benchmark problem. For this purpose, the RIP was experimentally determined as a function of the background water concentration present in the IMS drift tube. It is shown that simulation and experimental data are in very good agreement, demonstrating the validity of the method.
    Journal of the American Society for Mass Spectrometry 03/2013; · 3.59 Impact Factor
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    ABSTRACT: For the first time, ion mobility spectrometry coupled to rapid gas-chromatography using multi-capillary columns was applied for the development of a pattern of signs of life for the localisation of entrapped victims after disaster events (e.g. earth quake, terroristic attack). During a simulation experiment with entrapped volunteers, 12 human metabolites could be detected in the air of the void with sufficient sensitivity to enable a valid decision on the presence of a living person. Using a basic normalised summation of the measured concentrations, all volunteers involved in the particular experiments could be recognised only few minutes after they entered the simulation void. The analysis time is less than 3 minutes. An additional independent validation experiment enabled the recognition of a person in a room of ~25 m³ after approx. 30 minutes with high enough sensitivity to detect even short leaving of the room. It is doubtless that further work has to be done on analysis time and weight of the equipment but also on the validation during real disaster events. However, the enormous potential of the method as significantly helpful tool for search and rescue operations in addition to trained canines could be demonstrated.
    Analytical Chemistry 12/2012; · 5.82 Impact Factor
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    ABSTRACT: Presently, 2 to 4 days elapse between sampling at infection suspicion and result of microbial diagnostics. This delay for the identification of pathogens causes quite often a late and/or inappropriate initiation of therapy for patients suffering from infections. Bad outcome and high hospitalization costs are the consequences of these currently existing limited pathogen identification possibilities. For this reason, we aimed to apply the innovative method multi-capillary column-ion mobility spectrometry (MCC-IMS) for a fast identification of human pathogenic bacteria by determination of their characteristic volatile metabolomes. We determined volatile organic compound (VOC) patterns in headspace of 15 human pathogenic bacteria, which were grown for 24 h on Columbia blood agar plates. Besides MCC-IMS determination, we also used thermal desorption-gas chromatography-mass spectrometry measurements to confirm and evaluate obtained MCC-IMS data and if possible to assign volatile compounds to unknown MCC-IMS signals. Up to 21 specific signals have been determined by MCC-IMS for Proteus mirabilis possessing the most VOCs of all investigated strains. Of particular importance is the result that all investigated strains showed different VOC patterns by MCC-IMS using positive and negative ion mode for every single strain. Thus, the discrimination of investigated bacteria is possible by detection of their volatile organic compounds in the chosen experimental setup with the fast and cost-effective method MCC-IMS. In a hospital routine, this method could enable the identification of pathogens already after 24 h with the consequence that a specific therapy could be initiated significantly earlier.
    Applied Microbiology and Biotechnology 03/2012; 93(6):2603-14. · 3.81 Impact Factor
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    ABSTRACT: Although "uremic fetor" has long been felt to be diagnostic of renal failure, the compounds exhaled in uremia remain largely unknown so far. The present work investigates whether breath analysis by ion mobility spectrometry can be used for the identification of volatile organic compounds retained in uremia. Breath analysis was performed in 28 adults with an eGFR ≥60 ml/min per 1.73 m(2), 26 adults with chronic renal failure corresponding to an eGFR of 10-59 ml/min per 1.73 m(2), and 28 adults with end-stage renal disease (ESRD) before and after a hemodialysis session. Breath analysis was performed by ion mobility spectrometryafter gas-chromatographic preseparation. Identification of the compounds of interest was performed by thermal desorption gas chromatography/mass spectrometry. Breath analyses revealed significant differences in the spectra of patients with and without renal failure. Thirteen compounds were chosen for further evaluation. Some compounds including hydroxyacetone, 3-hydroxy-2-butanone and ammonia accumulated with decreasing renal function and were eliminated by dialysis. The concentrations of these compounds allowed a significant differentiation between healthy, chronic renal failure with an eGFR of 10-59 ml/min, and ESRD (p<0.05 each). Other compounds including 4-heptanal, 4-heptanone, and 2-heptanone preferentially or exclusively occurred in patients undergoing hemodialysis. Impairment of renal function induces a characteristic fingerprint of volatile compounds in the breath. The technique of ion mobility spectrometry can be used for the identification of lipophilic uremic retention molecules.
    PLoS ONE 01/2012; 7(9):e46258. · 3.53 Impact Factor
  • 60th Annual Conference on Mass Spectrometry and Allied Topics, Vancouver, BC, Canada; 01/2012
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    ABSTRACT: This experiment observed the evolution of metabolite plumes from a human trapped in a simulation of a collapsed building. Ten participants took it in turns over five days to lie in a simulation of a collapsed building and eight of them completed the 6 h protocol while their breath, sweat and skin metabolites were passed through a simulation of a collapsed glass-clad reinforced-concrete building. Safety, welfare and environmental parameters were monitored continuously, and active adsorbent sampling for thermal desorption GC-MS, on-line and embedded CO, CO(2) and O(2) monitoring, aspirating ion mobility spectrometry with integrated semiconductor gas sensors, direct injection GC-ion mobility spectrometry, active sampling thermal desorption GC-differential mobility spectrometry and a prototype remote early detection system for survivor location were used to monitor the evolution of the metabolite plumes that were generated. Oxygen levels within the void simulator were allowed to fall no lower than 19.1% (v). Concurrent levels of carbon dioxide built up to an average level of 1.6% (v) in the breathing zone of the participants. Temperature, humidity, carbon dioxide levels and the physiological measurements were consistent with a reproducible methodology that enabled the metabolite plumes to be sampled and characterized from the different parts of the experiment. Welfare and safety data were satisfactory with pulse rates, blood pressures and oxygenation, all within levels consistent with healthy adults. Up to 12 in-test welfare assessments per participant and a six-week follow-up Stanford Acute Stress Response Questionnaire indicated that the researchers and participants did not experience any adverse effects from their involvement in the study. Preliminary observations confirmed that CO(2), NH(3) and acetone were effective markers for trapped humans, although interactions with water absorbed in building debris needed further study. An unexpected observation from the NH(3) channel was the suppression of NH(3) during those periods when the participants slept, and this will be the subject of further study, as will be the detailed analysis of the casualty detection data obtained from the seven instruments used.
    Journal of Breath Research 09/2011; 5(4):046006. · 2.57 Impact Factor
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    ABSTRACT: A multi-capillary column ion mobility spectrometer (MCC/IMS) was developed to provide a method for the noninvasive diagnosis of lung diseases. The possibility of measuring the exhaled breath of mice was evaluated previously. The aim of the present study was to reveal whether mice affected by airway inflammation can be identified via MCC/IMS. Ten mice were sensitized and challenged with ovalbumin to induce allergic airway inflammation. The breath and volatile compounds of bronchoalveolar lavage fluid (BALF) were measured by MCC/IMS. Furthermore, histamine, nitric oxide, and arachidonic acid were determined as inflammatory markers in vitro. Six volatile molecules were found in the BALF headspace at a significantly higher concentration in mice with airway inflammation compared with healthy animals. The concentration of substances correlated with the numbers of infiltrating eosinophilic granulocytes. However, substances showing a significantly different concentration in the BALF headspace were not found to be different in exhaled breath. Histamine and nitric oxide were identified by MCC/IMS in vitro but not in the BALF headspace or exhaled breath. Airway inflammation in mice is detectable by the analysis of the BALF headspace via MCC/IMS. Molecules detected in the BALF headspace of asthmatic mice at a higher concentration than in healthy animals may originate from oxidative stress induced by airway inflammation. As already described for humans, we found no correlation between the biomarker concentration in the BALF and the breath of mice. We suggest using the model described here to gain deeper insights into this discrepancy.
    Journal of Applied Physiology 07/2011; 111(4):1088-95. · 3.48 Impact Factor
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    ABSTRACT: Volatile metabolites of Aspergillus fumigatus and Candida species can be detected by gas chromatography/mass spectrometry (GC/MS). A multi-capillary column - ion mobility spectrometer (MCC-IMS) was used in this study to assess volatile organic compounds (VOCs) in the headspace above A. fumigatus and the four Candida species Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis in an innovative approach, validated for A. fumigatus and C. albicans by GC/MS analyses. For the detection of VOCs, a special stainless steel measurement chamber for the microbial cultures was used. The gas outlet was either attached to MCC-IMS or to adsorption tubes (Tenax GR) for GC/MS measurements. Isoamyl alcohol, cyclohexanone, 3-octanone and phenethylalcohol can be described as discriminating substances by means of GC/MS. With MCC-IMS, the results for 3-octanone and phenethylalcohol are concordant and additionally to GC/MS, ethanol and two further compounds (p_0642_1/p_683_1 and p_705_3) can be described. Isoamyl alcohol and cyclohexanone were not properly detectable with MCC-IMS. The major advantage of the MCC-IMS system is the feasibility of rapid analysis of complex gas mixtures without pre-concentration or preparation of samples and regardless of water vapour content in an online setup. Discrimination of fungi on genus level of the investigated germs by volatile metabolic profile and therefore detection of VOC is feasible. However, a further discrimination on species level for Candida species was not possible.
    Mycoses 06/2011; 54(6):e828-37. · 1.28 Impact Factor
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    ABSTRACT: In the past decade, Ion Mobility Spectrometry has established a very strong foot hold in medical and biol. applications due to its numerous advantages including sensitivity, ruggedness and reproducibility. During the anal. of complex samples such as human breath, it is very probable that two or more analytes form peak clusters due to similar drift times and pre-sepn. times, thus hindering the identification of the analytes. Furthermore, such overlapping of signal makes quantification very difficult or even impossible. Resolving these peak clusters is important to enable proper identification and quantification of analytes detected for diagnosis. Hence, we designed a drift tube with variable length for investigating the influence of varying drift lengths and elec. field on resoln. Peak cluster formations usually seen between acetone and the reactant ion peak, between the dimer peaks of 2-Heptanone and 4-Heptanone have been resolved with the new drift tube after optimization. These novel drift tubes could easily negate the peak clusters often encountered when complex medical and biol. samples are measured with the ion mobility spectrometer. Furthermore, the fact that these drift tubes can be altered in length thereby providing a wide range of elec. fields (from 50 to 3300 V.cm-1), opens up new research options in ion motions in an elec. field. [on SciFinder(R)]
    International Journal for Ion Mobility Spectrometry 01/2011; 14(Copyright (C) 2011 American Chemical Society (ACS). All Rights Reserved.):31-38.
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    ABSTRACT: In nowadays life science projects, sharing data and data interpretation is becoming increasingly important. This considerably calls for novel information technology approaches, which enable the integration of expert knowledge from different disciplines in combination with advanced data analysis facilities in a collaborative manner. Since the recent development of web technologies offers scientific communities new ways for cooperation and communication, we propose a fully web-based software approach for the collaborative analysis of bioimage data and demonstrate the applicability of Web2.0 techniques to ion mobility spectrometry image data. Our approach allows collaborating experts to easily share, explore and discuss complex image data without any installation of software packages. Scientists only need a username and a password to get access to our system and can directly start exploring and analyzing their data.
    Journal of integrative bioinformatics 01/2011; 8(2):158.
  • Appl. Microbiol. Biotechn. 01/2011;
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    ABSTRACT: Below cloud scavenging processes have been investigated considering a numerical simulation, local atmospheric conditions and particulate matter (PM) concentrations, at different sites in Germany. The below cloud scavenging model has been coupled with bulk particulate matter counter TSI (Trust Portacounter dataset, consisting of the variability prediction of the particulate air concentrations during chosen rain events. The TSI samples and meteorological parameters were obtained during three winter Campaigns: at Deuselbach, March 1994, consisting in three different events; Sylt, April 1994 and; Freiburg, March 1995. The results show a good agreement between modeled and observed air concentrations, emphasizing the quality of the conceptual model used in the below cloud scavenging numerical modeling. The results between modeled and observed data have also presented high square Pearson coefficient correlations over 0.7 and significant, except the Freiburg Campaign event. The differences between numerical simulations and observed dataset are explained by the wind direction changes and, perhaps, the absence of advection mass terms inside the modeling. These results validate previous works based on the same conceptual model.
    Revista Brasileira de Meteorologia 12/2010; 25(4):437-447.
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    ABSTRACT: Multicapillary column (MCC) ion mobility spectrometers (IMS) are increasingly in demand for medical diagnosis, biological applications and process control. In a MCC-IMS, volatile compounds are differentiated by specific retention time and ion mobility when rapid preseparation techniques are applied, e.g. for the analysis of complex and humid samples. Therefore, high accuracy in the determination of both parameters is required for reliable identification of the signals. The retention time in the MCC is the subject of the present investigation because, for such columns, small deviations in temperature and flow velocity may cause significant changes in retention time. Therefore, a universal correction procedure would be a helpful tool to increase the accuracy of the data obtained from a gas-chromatographic preseparation. Although the effect of the carrier gas flow velocity and temperature on retention time is not linear, it could be demonstrated that a linear alignment can compensate for the changes in retention time due to common minor deviations of both the carrier gas flow velocity and the column temperature around the MCC-IMS standard operation conditions. Therefore, an effective linear alignment procedure for the correction of those deviations has been developed from the analyses of defined gas mixtures under various experimental conditions. This procedure was then applied to data sets generated from real breath analyses obtained in clinical studies using different instruments at different measuring sites for validation. The variation in the retention time of known signals, especially for compounds with higher retention times, was significantly improved. The alignment of the retention time--an indispensable procedure to achieve a more precise identification of analytes--using the proposed method reduces the random error caused by small accidental deviations in column temperature and flow velocity significantly.
    Analytical and Bioanalytical Chemistry 07/2010; 397(6):2385-94. · 3.66 Impact Factor
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    ABSTRACT: Exhaled breath can provide comprehensive information about the metabolic state of the subject. Breath analysis carried out during animal experiments promises to increase the information obtained from a particular experiment significantly. This feasibility study should demonstrate the potential of ion mobility spectrometry for animal breath analysis, even for mice. In the framework of the feasibility study, an ion mobility spectrometer coupled with a multicapillary column for rapid preseparation was used to analyze the breath of orotracheally intubated spontaneously breathing mice during anesthesia for the very first time. The sampling procedure was validated successfully. Furthermore, the breath of four mice (2 healthy control mice, 2 with allergic airway inflammation) was analyzed. Twelve peaks were identified directly by comparison with a database. Additional mass spectrometric analyses were carried out for validation and for identification of unknown signals. Significantly different patterns of metabolites were detected in healthy mice compared with asthmatic mice, thus demonstrating the feasibility of analyzing mouse breath with ion mobility spectrometry. However, further investigations including a higher animal number for validation and identification of unknown signals are needed. Nevertheless, the results of the study demonstrate that the method is capable of rapid analyses of the breath of mice, thus significantly increasing the information obtained from each particular animal experiment.
    Journal of Applied Physiology 03/2010; 108(3):697-704. · 3.48 Impact Factor
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    ABSTRACT: Sampling of breath under human control or automated control with sensors was combined with chem. detn. of a synthetic sample using multi-capillary column ion mobility spectrometry to measure quant. variability. Variation was 19% with an automated inlet and 33% with human control. Sensors to operate an automated inlet were also evaluated with human subjects and included carbon dioxide (CO2), flow (direction and velocity), vol. (integrated from the flow rate) and humidity, all operating in the mainstream of exhaled air. The flow sensor provided a measure of sampling of breath from the upper airways and other sensors gauged exclusive sampling of the end-tidal vol. as well. Sensors for vol. and CO2 exhibited identical profiles, using appropriate threshold values, in ref. to inspiration and expiration. A sensor for humidity lagged inspiration and expiration with a delay of 300 ms and therefore is diminished in value. The sensors recommended for an automated inlet for breath sampling are CO2 and the exhaled or tidal vol. though tidal vol. varies significantly with personal physiognomy. This necessitates an evaluation of a subject to establish a threshold setting and CO2 is the single best parameter providing the availability of sensor signal within 50 ms. [on SciFinder(R)]
    International Journal for Ion Mobility Spectrometry 01/2010; 13(1):41-46.
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    ABSTRACT: Propofol (2,6-diisopropylphenol) – ein Injektionsanästhetikum – kann direkt in der Atemluft detektiert und quantifiziert werden. Zur Messung von Propofol in der Atemluft wurde ein mit einem ß-Strahler ausgestattetes Ionenmobilitäts- Spektrometer in Verbindung mit einer Multikapillarsäule zur schnellen Vortrennung (Sekunden bis Minuten) genutzt. Volatile Analyte werden ionisiert und in einem elektrischen Feld beschleunigt. In der Driftstrecke zum Detektor werden die Moleküle im Strom gegen ein Driftgas nach Größe, Gewicht und Form aufgetrennt. Aus der gemessenen Driftzeit wird in einigen Millisekunden die Ionenmobilität berechnet. Zusammen mit der Retentionszeit aus der Multikapillarsäule ist eine selektive Identifikation der Analyten möglich. Die Signalintensität ist ein Maß für die Molekülkonzentration. Der Vergleich der Propofol-Atemluftkonzentrationen (300 pptV – 5 ppbV) und der Propofol-Serum Konzentration zeigte eine correlation von 0.73. MCC-IMS ist eine geeignete Methode zur Quantifizierung von Propofol in der Atemluft. Die Anwendung zur Vorhersage der Serum-Propofolkonzentration zur Narkosesteuerung scheint möglich.
    Biomedizinische Technik. 01/2010; 55(Suppl. 1).
  • Pneumologie 01/2010; 64.

Publication Stats

414 Citations
77.20 Total Impact Points

Institutions

  • 2008–2014
    • Leibniz-Institut für Analytische Wissenschaften
      Dortmund, North Rhine-Westphalia, Germany
  • 2010–2012
    • Universitätsmedizin Göttingen
      • Center for Anesthesiology, Emergency and Intensive Care Medicine
      Göttingen, Lower Saxony, Germany
  • 2007
    • Martin Luther University of Halle-Wittenberg
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 2003
    • Technische Universität Dortmund
      Dortmund, North Rhine-Westphalia, Germany