Airborne analytics - drone-compatible ion mobility spectrometer with optional gas chromatograph for rapid assessment of chemical hazards

• Applicant: Professor Dr.-Ing. Stefan Zimmermann
• Subject Area: Measurement Systems
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 540972827

With increasing availability of small camera drones, there is a growing interest in many areas to install additional measurement technology on such flying platforms. In particular, remote sensing by drone (UAV) is highly interesting in safety and security applications and environmental monitoring where large areas need to be investigated rapidly without putting first responders at risk. Therefore, this project focuses on the development of a drone-compatible ion mobility spectrometer (IMS) with analytical capabilities way beyond simple gas sensors and gas sensor arrays for rapid and sound assessment of complex chemical hazards. Due to strict boundary conditions, such as limited size, weight, and power consumption, commercial IMS and those existing from preliminary work with sufficient analytical performance cannot be coupled easily to drones. This requires completely new system concepts and a holistic system design taking into account all boundary conditions and analytical parameters. Specifically, this project aims for the development of a design strategy including the hardware implementation and evaluation in flight of a drone-compatible dual IMS with non-radioactive ionization source, weight <= 1000 g, power consumption <= 10 W, high resolving power R >= 60, detection limits in the low ppt range at measurement times <= 1 s, integrated heaters reaching 80 °C for short response times, and a sampling rate of at least 1 Hz for a spatial resolution of at least 10 m at high flight velocity of 10 m/s. A particular challenge is decoupling of the drone and the measurement signal by an IMS design adapted to the drone related interferences. Specifically, the frequency spectrum of the IMS signal will be shifted out of the frequency spectrum of the drone related interferences by drift tube design. Another objective is to determine the measurement uncertainty according to GUM with respect to the analyte concentration. In particular, for mixtures and variable humidity, as found in most real applications, the measured concentration does usually not resemble the actual concentration, since the number of ionized analyte molecules and thus the peak area in the ion mobility spectrum not only depends on the concentration, but is determined by the thermodynamic equilibrium of the chemical ionization reactions in the gas phase. Therefore, a drone-compatible gas chromatograph (GC) for quantitative analysis of real air samples by GC-IMS will be developed as well, and the measurement uncertainty according to GUM of the GC-IMS will be investigated. For rapid remote sensing of large areas, the UAV-IMS can then be used, while the GC can be remotely coupled to the IMS on demand when a quantitative analysis of a sensitive area by UAV-GC-IMS is required.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2433: Metrology on flying platforms