Leibniz Universität Hannover Faculty Faculty of Electrical Engineering and Computer Science
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Institute of Electrical Engineering and Measurement Technology
 
Institute of Electrical Engineering and Measurement Technology Sensors and Measurement Technology
Research Projects
Completed Research Projects

Research Projects of the Department of Sensors and Measurement

  • Split-ring resonator as detector for liquid and ion chromatography
    The analysis of food and drugs, as well as the monitoring of chemical processes and bioreactors, requires the use of high-performance liquid chromatography (HPLC) and ion chromatography. These processes are best conducted with universal, cost-effective, and sensitive detectors. This project focuses on the use of a split-ring resonator, which detects changes in the electrical and dielectric properties of the eluate from liquid chromatography or ion chromatography by monitoring the amplitude of the transmitted signal using an envelope detector.
    Year: 2023
  • Coated Blade Spray Ion Mobility Spectrometry
    Coated Blade Spray (CBS) is a microextraction technology with blades that serve as both the extraction device and the electrospray ionization (ESI) emitter. This project focuses on coupling CBS with our ESI-IMS. The capability of CBS-IMS to detect benzodiazepines and ketamine in drinks and the pesticide isoproturon in water samples has been demonstrated.
    Year: 2022
  • Surveillance and Reconnaissance Techniques for Chemical & Biological Threads
    Surveillance and Reconnaissance Techniques for Chemical & Biological Threads (TeChBioT) aims for the development of a miniaturized, low cost, gas chromatography-ion mobility spectroscopy (GC-IMS) instrument that enables fast detection and identification of volatile and low-volatile chemical (CWA) and non-volatile biological warfare agents (BWA).
    Year: 2022
    Funding: European Union’s European Defence Fund (EDF) under grant agreement No 101103176
  • SIIRI (A03)
    The aseptic loosening is one of the main reasons for revision surgery in total hip arthroplasty. During the loosening process of hip stems, tolerable relative movements of 30-100 µm between stem and bone are exceeded and induce a characteristic progressive loosening cascade that leads to a gradual loss of fixation due to a degradation of the surrounding bone. Up to date, there is no reliable diagnostic method to detect such a loosening at an early stage. The aim of subproject A03 is to enable an early detection of an hip stem loosening and to be able to distinguish aseptic from septic loosening in order to counteract an excessive bone destruction early enough.
    Year: 2021
    Funding: This research is founded by the German Research Foundation (DFG)
  • SIIRI (A06)
    Cochlear implants (CI) are neuro-implants that replace the function of the inner ear in cases of profound deafness. However, due to malpositioning and cell occupation, functionality can be significantly impaired, leading to reduced electrical stimulation efficiency and thus to a loss of implant function and thus hearing. Therefore, the aim of this project is to develop a new impedance spectrometric method to detect misplacements and cell occupations on CI stimulation electrodes.
    Year: 2021
    Funding: This research is founded by the German Research Foundation (DFG)
  • Ultra-fast detection in droplet microfluidics using ion mobility spectrometry
    The aim of this project is the fast, label-free detection of individual droplets in microfluidic chip systems using IMS. The challenge is to explore the possibilities and limits of this promising detection method for droplet microfluidics and to enable the label-free detection of individual droplet contents at high throughput.
    Year: 2021
    Funding: This research is founded by the German Research Foundation (DFG)
  • GC-IMS measurements of volatile anaesthetics
    This project focuses on all topics related to trigger-free anaesthesia for patients threatened by malignant hyperthermia. With our GC-IMS, especially medical devices and indoor air will be examined for traces of volatile anaesthetics. For example, these substances can be detected in an average concentration of 120 ppb in postanaesthesia care units.
    Year: 2020
  • Electromagnetic Simulations
    Electromagnetic simulations offer an insight into electric and magnetic field distributions or radiation characteristics of arbitrary structures, such as transmission lines, filters or antennas. Furthermore, determination of scattering parameters allows a description of transmission and reflection characteristic of electromagnetic waves. In current research, electromagnetic simulations with CST Microwave Studio are used, e.g. to support the design process of electromagnetic sensors.
    Year: 2020
  • Ion mobility spectrometry coupled to chip-based electrochromatography
    In this cooperation project with the group of Professor Belder from the Leipzig University a chip electrochromatography (ChEC) is coupled to a compact electrospray ion mobility spectrometer (ESI-IMS) from our group. The aim of this work is to characterize ESI-IMS as detector for chip based separation techniques. Furthermore, secondary ionization with APPI and APCI sources is implemented in the desolvation region of the ESI-IMS to enable the detection of compounds that cannot be ionized by electrospray.
    Year: 2019
    Funding: This research is founded by the German Research Foundation (DFG)
  • New ionization sources and fast gas chromatography coupled to a mobile mass spectrometer for hazardous substance detection (GC-Plasma-TOF)
    Aim of this research project is a mobile system for fast detection of hazardous substances for first responder applications. For this purpose, a mobile mass spectrometer will be coupled to a fast gas chromatograph for fast analysis of complex samples. Furthermore, four different ionization methods will be employed to improve both substance identification and limits of detection. Our focus is the development of a new plasma source.
    Year: 2019
    Funding: Supported by the German Federal Ministry of Education and Research (BMBF), Grant 13N14888
  • Electron capture detector with non-radioactive electron source
    Gas chromatographs equipped with electron capture detectors (ECD) are widely used for the analysis of electron affine substances such as pesticides, herbicides or chlorofluorocarbons. Achieving limits of detection in the low pptv-range, electron capture detectors are the most sensitive detectors available for such compounds. Based on their operating principle, they require free electrons at atmospheric pressure, which are usually generated by using a β--decay. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation and disposal. Therefore, we developed a new electron capture detector using our non-radioactive electron source, which is not subject to these limitations and offers further advantages such as adjustable and higher electron densities and energies.
    Year: 2017
  • High Pressure HiKE-IMS (HiP-HiKE-IMS)
    The above described HiKE-IMS is a powerful device for detecting low electron and proton affine substances invisible for conventional IMS. Typical cross sensitivities to e.g. water are significantly reduced and additional separation by alpha-function improves compound identification. By increasing the operating pressure, the system can be miniaturized, the power consumption reduced and the limits of detection significantly improved. Therefore, in this project, we develop optimized drift tubes based on PCBs, which are able to maintain high reduced field strengths at significantly increased pressures. Such a PCB-HiKE-IMS can be operated at 60 mbar with detections limits in the low ppbv level, e.g. for benzene even in the presence of high toluene and water concentrations. The resolving power for benzene is R = 100 at a drift length of 15 cm. The used vacuum pump is just 194 x 115 x 77 mm³.
    Year: 2017
    Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under the grant 13N14469
  • Early adequate sepsis therapy using ion mobility spectrometry based diagnostics
    Aim of this project is the development of an innovative method for rapid pathogen identification of sepsis patients by headspace analysis of standard blood cultures using gas chromatography ion mobility spectrometry (GC-IMS). In contrast to the current care situation this method should lead to a result after a few hours, while the analysis itself only takes a few minutes. For this purpose, we develop a dual polarity IMS with a non-radioactive ionization source being able to detect positive and negative ions simultaneously. This allows the analysis of both ion polarities with just a single GC run.
    Year: 2017
    Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under the grant 13GW0191D
  • Miniaturized ion mobility spectrometer
    Aiming for mobile and hand-held applications miniaturized ion mobility spectrometer drift tubes are required. With its outer dimensions of only 15 mm x 15 mm in cross section and an overall length of 56 mm, the mini-IMS is one of our smallest high-performance drift tube IMS with a resolving power of Rp = 63 and detection limits in the mid pptv-range for 1s of averaging. For easy integration, the miniaturized drift tube is designed to fit commercially available DIP sockets (7.62 mm row-to-row spacing, 34 pins with 2.54 mm pitch). This enables direct connection of the drift tube to the driver electronics. Different ionization sources (radioactive and non-radioactive) can be operated with this drift tube.
    Year: 2017
  • Ultra-fast polarity switching ion mobility spectrometer
    It is well known that depending on their gas phase energetic properties, different substances may form positive ions, negative ions or even ions of both polarities in some cases. Thus, non-targeted measurements or measurements aiming to monitor a variety of substances require analyzing ions of both polarities, e.g. in GC-IMS applications. In this project, an ion mobility spectrometer which is able to perform a polarity switch in less than 10 ms has been developed. This allows switching the measurement polarity after every spectrum, thus enabling real-time monitoring of ions of both polarities with a single drift tube and obviating the need for expensive twin drift tubes.
    Year: 2016
    screenshot of a dual-polarity ion mobility spectrum screenshot of a dual-polarity ion mobility spectrum © GEM
  • Nanosensors
    Many medical, biotechnological, safety and security applications require highly sensitive and selective sensors. Due to special properties of nano-objects, they can be used to optimize the analytical performance of existing sensors systems. Therefore, we are working on new sensor solutions using nanoparticles, nanowire or other nano-objects.
    Year: 2016
  • Ultra-sensitive atmospheric pressure chemical ionization mass spectrometry
    In various applications trace gas concentrations in the ppt-range need to be detected in less than a second. Due to an increasing number of contaminants present at ppt-levels ultra-high sensitivity also requires excellent selectivity. Our approach to achieve this combination is to push highly selective mass spectrometer (MS) towards extreme sensitivities by coupling atmospheric pressure ionization sources (API) to time-of-flight mass spectrometers (ToF-MS). For example, a radioactive Tritium (³H) ionization source coupled to a Bruker micrOTOF II leading to ppq detection for protonated Acetone.
    Year: 2016
  • Non-invasive monitoring of bacterial growth in a bioreactor
    In order to monitor dynamic changes in the exhaust gas composition of a bioreactor, our GC-IMS can be used. The system enables automatic sampling and detection of more than 100 compounds during every exhaust gas analysis.
    Year: 2016
  • Identification of bacteria regarding metabolic products
    Bacteria emit characteristic metabolic products. Using our ultra-high sensitive GC-APCI-MS, we are able to distinguish between different bacterial species and even different bacterial type strains.
    Year: 2016
  • X-Ray Ion Mobility Spectrometer
    For the ionization of gaseous samples, most ion mobility spectrometers employ radioactive ionization sources, e.g. containing 63Ni or 3H. Besides legal restrictions, radioactive materials have the disadvantage of a constant radiation with predetermined intensity. The aim of this research project is the realization and characterization of an X-ray IMS. Therefore, the 3H-source of our previously described compact high resolution IMS was replaced by a commercially available X-ray source. The realized setup maintains the high resolving power of R = 100 at a drift length of 75 mm and shows very good detection limits in the low pptv-range.
    Year: 2016
  • Field asymmetric time of flight ion mobility spectrometry
    In this work, we are developing a new concept for miniaturized and low cost ion mobility spectrometers (IMS) manufactured from printed circuit boards (PCB). The goal is a system which is small and cheap, but provides the analytical power of high end systems. To achieve this, we try to combine the advantages of time of flight IMS (TOF-IMS) and field asymmetric IMS (FAIMS) by inserting a chamber with an alternating electrical field into the drift tube of a PCB based TOF-IMS.
    Year: 2016
    Funding: This work has been supported by the German Federal Ministry of Economics and Technology (BMWi), under the Grant KF3238301NT3 upon decision of the German Bundestag
  • Nano-Q
    Aim of this cooperation project is the development of a mercury sensor system for personal air monitoring (PAM). The sensor system is based on applications of nanogranular materials. The major tasks are the construction of a mercury test bench for the adjustment of lowest mercury concentrations and the characterization of the mercury sensors.
    Year: 2016
    Funding: This project is sponsored by the Federal Ministry of Education and Research. (13XP5011B)
  • ESI-IMS
    Aim of this research project is the detection and analysis of pesticide and drug residues present in ground and surface water. Electrospray ionization (ESI) is a commonly used ionization method for the analysis of liquids. We coupled an electrospray ionization source with a 75mm desolvation tube to our high resolution ion mobility spectrometer with a 75mm drift tube length. One major advantage of our setup is that the desolvation region of the ESI-IMS can be heated separately from the drift region. With this setup we reach e.g. a resolving power of R=100 for tetraalkylammonium halides and at a water content of 50% and after 2s of averaging a LOD of 4 µg/l for bentazon.
    Year: 2016
  • Data acquisition software for ion mobility spectrometers
    In order to control all parameters of a measurement setup, carry out automated measurements and analyze the generated data, a custom software suite has been developed using LabVIEW. It allows direct control of both our custom-built bus system as well as external devices, acquires and stores ion mobility spectra together with all relevant measurement parameters and allows the user to implement additional custom functions through a special scripting language.
    Year: 2016
  • Measurement electronics
    Virtually every measurement setup requires various control signals and a data acquisition system in order to function. The performance of these devices has a significant impact on the overall performance of the entire measurement setup. Thus, crucial components such as fast high voltage switches or picoampere amplifiers as well as a modular bus system were developed and manufactured in-house.
    Year: 2016
  • Non-radioactive electron sources for fast high sensitive sensor systems
    Most ion mobility spectrometers (IMS) employ a radioactive β-source to ionize the target analytes. However, because of the potential hazards and the associated handling restrictions regarding radioactive materials non-radioactive ionization sources are of increasing importance. The aim of this research project is the development of non-radioactive electron sources, which are used both in ion mobility spectrometry for ionization as well as in other sensor systems. Here, one advantage is that non-radioactive electron sources generate identical ion species as radioactive electron sources. A further advantage of non-radioactive electron sources is the controllability of the electron emission and hence the ionization process and the consequent opportunity to develop completely new sensor principles.
    Year: 2016
    Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under the grant 13N12820.
  • Chemical ionization detector for gas chromatography
    Ion mobility spectrometers deliver limits of detection in the low pptv-range within a measuring time of less than a second. The goal of this project is to transfer this sensitivity to a simple low-cost detector for gas chromatography.
    Year: 2016
  • High kinetic energy ion mobility spectrometry (HiKE-IMS)
    The crucial problem in most real-life applications of ion mobility spectrometers is the sample ionization, as it limits the detectability of many substances and is the primary source of matrix effects. In this project, a novel approach using reactant ions with high kinetic energy at reduced pressure is employed in order to minimize these problems and even allow quantitative measurements using ion mobility spectrometers. For example, it is possible to detect ppbv-concentrations of benzene in the presence of toluene and xylene in ppmv-concentrations
    Year: 2016
    Funding: This research is founded by the German Research Foundation (DFG)
  • Closed gas loop, high-resolution IMS with gas chromatographic pre-separation for breath gas analysis
    In many breath gas analysis applications, real-time and bed-site analysis is required to achieve true applicability for clinical diagnosis. Thus, we built a compact, closed gas loop, high-resolution GC-IMS. The ion mobility spectrometer achieves a mobility resolution of R=90. The GC-IMS is equipped with a filter re-circulation system providing a continuous supply of dry and clean drift gas, so that no external supply is needed. Hence, the entire system fits in a 19″ housing (6 RU height).
    Year: 2016
  • FEM simulation of ion trajectories within ion mobility spectrometer or mass spectrometer
    Using FEM Software (Comsol Multiphysics), ion trajectories within ion mobility spectrometers (IMS) at atmospheric pressure or within mass spectrometers (MS) at vacuum conditions are simulated. Depending on the application, the influence of diffusion, migration, charge repulsion, ion generation and the transient electric field are considered. The simulation results are used to optimize IMS or MS operating parameters and geometry.
    Year: 2016
  • Mercury vapor sensor
    The aim of this project is to develop a miniaturized mercury sensor to monitor the mercury concentration in air. Mercury forms amalgam in connection with gold. This effect can be used to determine the presence and concentration of mercury, since the formation of amalgam influences various physical parameters.
    Year: 2016
  • IMS MS coupling
    To identify the underlying ion species in ion mobility spectra, we couple our IMS devices to mass spectrometers (MS). A simple gated interface has been designed to transfer selected peaks of the ion mobility spectrum into the MS. By using this coupling, we investigate the occurring ion-molecule reactions in our ambient pressure DT-IMS or HiKE-IMS.
    Year: 2015
    Funding: This research is founded by the German Research Foundation (DFG)

Last Change: 02.06.25 Print

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