Handheld micromechanical cantilever mass sensor for early detection of carbon nanoparticles

This paper describes the first evaluation of development and real-time performance of a low-cost handheld cantileverbased airborne nanoparticle (NP) detector (CANTOR-1). 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 for collecting the ENPs from the air stream to the cantilever surfaces and measuring their mass concentration, respectively. Moreover, to realize a real-time measurement, a frequency tracking system based on phase-locked loop (PLL) is built and integrated to the device. A 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. By means of the device calibrations performed with a standard ENP monitoring instrument of fast mobility particle sizer (FMPS, TSI 3091), a measurement precision of ENP mass concentration of < 55% and a limit of detection (LOD) of < 25 mug/m(exp 3) are obtained.