| Abstract |
Tunable Atomic Line Molecular Spectroscopy (TALMS) is a high resolution, differential absorption technique used in the ultraviolet region. Under Interagency Agreements EPA-80-D-X1014 and AD-89-F-2A008 with Lawrence Berkeley Laboratory, two prototype TALMS instruments were designed, constructed, and delivered to the U.S. EPA at Research Triangle Park, North Carolina. TALMS I was a large laboratory instrument designed to demonstrate the feasibility of TALMS detection of toxic organic compounds. TALMS II was a more compact monitor for benzene designed for possible field applications. Both instruments were evaluated in the laboratory for performance characteristics in the analysis of benzene using the 253.7 nm mercury line. The tests included detection limit, precision, effect of temperature (TALMS I), effect of pressure (TALMS II), and interferences from organic compounds other than benzene. The prototype instruments evaluated can detect benzene precisely above the detection limit of 6 microgram. The apparent interferences from toluene and pyridine are relatively small and may be artifacts which can be eliminated with improvements in electronic signal processing. It was recommended that changes to the sample cell and electronics be made to improve the detection limit and that extension of the capabilities of TALMS to other organic compounds be made. |
