Semi-continuous Determination of Anions, Cations & Heavy Metals in Aerosols

Metrohm presents PILS-IC-VA, a new instrumental approach coupling a particle-into-liquid-sampler (PILS) to a dual-channel ion chromatograph (IC) for measuring aerosol anions and cations and a voltammetric measuring stand (VA) to determine the heavy metals.

PILS-IC-VA is a tool to capture the short-term impact of air pollution as it allows the near real-time determination of the aerosol composition of ambient air. Moreover, this hyphenated system is highly suited for long-term unattended field use in remote regions.

Common filter-based measurements suffer from their poor temporal resolution and their labor-intensive offline management. Thus, acute exposures that appear only for a very short time get lost in the long averaging times of the filter. The automated PILS, on the other hand, yields enhanced time-resolved data by permanently collecting airborne particulate matter. It allows the capture of particles in an air flow and the dissolving of soluble constituents in a steam jet for subsequent analysis.

The captured air particles, which are sampled through a cyclone that controls the size of the entering particles applying a size threshold of 10 µm (PM10), enter the condensation growth chamber, where they are mixed with injected supersaturated steam. Rapid adiabatic mixing allows the aerosol particles to grow into droplets large enough to be collected by an impactor. Afterwards, the solution with the diluted aerosol particles is split into three streams and analyzed by dual-channel ion chromatography and voltammetry.