Sampler: glass tube, 7-cm long, 6-mm OD, 4-
mm ID, flame-sealed ends, containing two
sections of activated (600 °C) coconut shell
charcoal (front - 100 mg; back - 50 mg)
separated by a 2-mm urethane foam plug. A
silylated glass wool plug precedes the front
section and a 3-mm urethane foam plug follows
the back section. Pressure drop across the tube
at 1 L/min airflow must be less than 3.4 kPa.
Tubes are comm ercially available