A cyclone in front of the SKC DPM Cassette is used to remove large particles that might clog the small orifices of the cassette's built-in impactor. The cut-off size of the cyclone is not very important as long as particles larger than 3 μm are removed efficiently. The SKC DPM Cassette can be used without a cyclone if sampling is performed in an environment where the concentration of large particles is known to be very low.

The SKC DPM Cassette was developed/tested for use in mines. Therefore, it was evaluated at the flow rates used by the U.S. Mine Safety & Health Administration (MSHA): 1.7 L/min in metal/non-metal mines; 2.0 L/min in coal mines.

The second filter is used for organic carbon, not as a blank. Results are a summation of elemental carbon plus organic carbon to give a total carbon. For a “blank,” use a blank DPM Cassette.

The cassettes have an expiration date because they can pick up contaminants over time, which will add to the total carbon detected.The cassettes have an expiration date because they can pick up contaminants over time, which will add to the total carbon detected.

The risk of using a DPM Cassette beyond its shelf-life is that the background may not be acceptable. Cassettes used beyond shelf-life should be tested for background to determine suitability for sampling and analysis. SKC does not recommend use of DPM Cassettes beyond the shelf-life indicated.