The development of a new clean air sampling system for the Department of Energy's WB-57F aircraft has allowed the analysis of CCl3F (Fluorocarbon-11), Ccl2F2 (Fluorocarbon-12), CHClF2 (Fluorocarbon-22), C2Cl3F3 (Fluorocarbon-113), CH4, CO, CO2, N2O, CH3Cl, CCl4, CH3CCl3, OCS and SF6 in tropospheric and stratospheric samples. Samples collected during the interception of the plume from the eruption of Mount St. Helens indicate that OCS was injected into the stratosphere during the eruption. A large CO2 gradient was found at 19.2 km on this flight.