A personal sampler for direct mass determination of nano-particles using a resonant cantilever sensor

Work place monitors and personal samplers are demanded to assess the exposure of production workers by engineered airborne nanoparticles. Comparatively complex and costly instrumentation, which is often too large for personal mobile operation, is already available. In this joint research project MEMS-cantilevers of slender geometry providing a large surface-to-volume ratio, driven at resonance by a piezoelectric stack placed below the cantilever, were used for sensing. A mass resolution of 5 ng was observed. The core parts for sampling are matching the specifications for mobile operation. Important considerations for the development were: Low production costs (< 200 Euro), battery lifetime of at least 8 h (one shift), sampler weight below 500 g, sufficient stability against climate changes, rugged design. The personal sampler is validated in environmental test chambers against test aerosols generated from technical nano-particles (SiO2, carbon, TiO 2, Ag, PTFE).