ACM - Aerosol Collection Module
The Aerosol Collection Module (ACM) is a device for quasi-online sampling and measurement of the particulate phase of an aerosol. The ACM samples particles and after preconcentration transfers them to a gas phase detector (e.g. PTR-TOF-MS) for analysis of the aerosol composition.
The aerosol sample is drawn into the ACM through the inlet. The particles are focused on a narrow beam via an aerodynamic lens. In collection mode, the particle beam impacts on the cooled surface of the collector. When switched to desorption mode, the valve to the evacuated chamber is closed and the collector is heated up. By this, the particles evaporate and are desorbed from the collector surface. A carrier gas flushes the evaporated aerosols from the collection area and transfers them through a valve system to the connected gas phase detector, where they can be analyzed. By simultaneous measurement of particle and gas phase composition the partitioning of semi-volatile organic compounds between the gaseous and the particulate phase of the sample can be quantified.
The ACM was developed in the group Stable Isotopes in Aerosols in collaboration with Aerodyne research Inc. It is currently used in simulation chamber studies and continuously improved with respect to sampling efficiency and user friendliness.