Partially integrated cantilever-based airborne nanoparticle detector for continuous carbon aerosol mass concentration monitoring

• Published in: Journal of sensors and sensor systems Vol. 4; no. 1; pp. 111 - 123
• Main Authors: Wasisto, H. S., Merzsch, S., Uhde, E., Waag, A., Peiner, E.
• Format: Journal Article
• Language: English
• Published: Gottingen Copernicus GmbH 01.01.2015; Copernicus Publications
• Subjects: Aluminum; Carbon; Etching; Flow velocity; Microelectromechanical systems; Monitoring; Nanomaterials; Nanoparticles; Nanotechnology; Phase locked loops; Phase locked systems; Real time; Sensors; Service life assessment; Silicon wafers; Time measurement; Tracking systems; Ultrasonic cleaning; Ultrasonic testing; Workplaces
• ISSN: 2194-878X; 2194-8771; 2194-878X
• DOI: 10.5194/jsss-4-111-2015

The performance of a low-cost partially integrated cantilever-based airborne nanoparticle (NP) detector (CANTOR-1) is evaluated in terms of its real-time measurement and robustness. The device is used for direct reading of exposure to airborne carbon engineered nanoparticles (ENPs) in indoor workplaces. As the main components, a miniaturized electrostatic aerosol sampler and a piezoresistive resonant silicon cantilever mass sensor are employed to collect the ENPs from the air stream to the cantilever surfaces and to measure their mass concentration, respectively. Moreover, to realize a real-time measurement, a frequency tracking system based on a phase-locked loop (PLL) is built and integrated into the device. Long-term ENP exposure and a wet ultrasonic cleaning method are demonstrated to estimate the limitation and extend the operating lifetime of the developed device, respectively. By means of the device calibrations performed with a standard ENP monitoring instrument of a fast mobility particle sizer (FMPS, TSI 3091), a measurement precision of ENP mass concentrations of < 55% and a limit of detection (LOD) of < 25 μg m−3 are obtained.