Abstract: An improved atmospheric spiking method and apparatus includes an 8-port valve is located between a tube desorber and a sample concentrator. The 8-port valve, tube desorber, and sample concentrator are timed to perform the following steps:1. Load the sorbent robe into the tube desorber.2. Connect a reference substance source with a tube having a fixed, predetermined volume.3. Connecting the fixed volume robe to a purge gas source at one end and to a sorbent tube to be spiked at the other end, so that a known volume of the reference substance may be spiked onto the tube.4. Connecting the spiked sorbent robe at one end to the purge gas supply and at the other end to the sample concentrator so that the tube may be desorbed.