Abstract by Elaura Gustafson
Chemistry and Biochemistry
Charge detection mass spectrometry of microparticles using printed circuit board electrode arrays
We are developing a charge-detection mass spectrometer that will measure the charge and mass of microparticles including dust grains in the Martian atmosphere. This analyzer will be a linear detector array using multiple charge-sensing stages and a central DC region on the facing surfaces of two printed circuit boards. Laboratory testing includes a vacuum chamber setup that simulates Mars conditions and an electrospray source to produce charged microparticles. The charge detector will provide the charge, velocity and kinetic energy of the particles. Mass can be calculated from these measurements. For a given DC voltage, particles with m/z too high don’t have the correct speed for the resulting signal to be discernible. Particles with m/z too low are deflected onto the circuit board. Between these extremes is a range of m/z values suitable for producing analyzable signals. The central DC region is adjustable over the range 0.1 to 360 V. This is sufficient to produce measurable speeds of particles up to 11 μm in diameter with at least 10,000 charges.