What is the highest flowrate that can be used for sorbent tube sampling?
This will be dependent on the sorbent tube being used, the environment being sampled, and the expected concentrations. If the sorbent tube has a small diameter and contains tightly packed sorbent material of a small mesh size, the maximum flowrate will be limited by the sampling pump’s ability to overcome the high back pressure (resistance). If the environment being sampled contains many interfering compounds or high humidity, the maximum air flow (and air volume) should be limited to reduce the chance of sample breakthrough. If the expected concentrations are high, the flow rate may need to be reduced to avoid overloading the capacity of the sampling device. Consult the method to determine the maximum flow rate and breakthrough volumes. Typically, flowrates using sorbent tubes are between 20 and 200 ml/min, with maximum flows not to exceed 1 liter per minute.
