Automated sequential sampler for collection of highly volatile atmosphericcontaminants

Rapid and accurate measurement of atmospheric concentrations of highly vola tile organic compounds is important in obtaining reliable information for t he assessment of environmental pollution or the volatilization mechanisms o f the chemicals. Nonmechanized sample collection requires intensive labor a nd effort, and may cause large random or systematic errors. An automated so lenoid switching system has developed to assist in obtaining precise enviro nmental concentrations of highly volatile organic compounds. The design, co nstruction, and operation are described in the paper for potential applicat ion in similar studies Using this sampling system, two experiments were con ducted to determine atmospheric volatilization flux density of three highly volatile and reactive organic compounds (methyl bromide, 1,3-dichloroprope ne, and propargyl bromide). The automated solenoid switching system signifi cantly reduced the requirements for labor and time. Results from the two ex periments indicate that reliable sample collection was achieved. The automa ted sampling system was also relatively inexpensive and can be easily modif ied to accommodate a variety of sources, sampling intervals, and multiple n umber of solenoid valves.