With the intensification of air pollution, the monitoring of the chemical composition of aerosols (particulate matter «PM») is becoming more and more important.
However, traditional filter membrane sampling methods are time-consuming and labor-intensive, and the collected samples need manual pretreatment. The usual sampling period is several days, which cannot provide higher temporal resolution monitoring for rapidly changing air pollution. Metrohm Process Analytics presents a new member to their portfolio: the Metrohm AeRosol Sampler «MARS». The MARS is a device used to capture particles in an air flow and dissolve the soluble constituents in a steam jet for further analysis (e.g., ion chromatography – IC, or voltammetry – VA).
Image credit: Metrohm Middle East FZC
Inline sample analysis
The principle of the aerosol sampler is simple. Air is continuously entering the MARS through the Wet Rotating Denuder (WRD) to remove the interfering gases. The ambient air, stripped of its gaseous water-soluble components, enters the Steam-Jet Aerosol Collector (SJAC). Super saturated steam is introduced, causing the aerosols to grow into larger, heavier droplets. Further on the air passes through a cyclone, collecting the particles in water by inertial separation. The resulting solution of dissolved ionic aerosol species is continuously sampled at the bottom of the SJAC for further analysis.
Easily to couple with different analysis techniques
The MARS can be used as a preconditioning unit for several analytical applications in ambient or industrial environments. An ion chromatograph (IC) could be coupled directly to the MARS for analysis of anions and cations in aerosols. When monitoring ambient air particulate matter with MARS-IC, an internal standard can be added. This internal standard contains a known amount of Lithium and Bromide which ensures a continuous validation of the results. On the other hand, heavy metals can also be analyzed by coupling the MARS with a voltammetry instrument, enabling comprehensive analysis of your sample. When this instrument is combined with an IC or VA instrument, it can be controlled remotely to evaluate results immediately from MagIC Net or Viva respectively.
Get to know the MARS