Portable sensor for hazardous waste. Topical report, October 1993--September 1994

We describe an innovative technique to detect hazardous materials at sub part-per-billion levels. Our approach exploits active nitrogen energy-transfer (ANET) to excite atomic and molecular fluorescence characteristic of various hazardous species. ANET excitation is very state specific, generating simple spectra that are easily detected with instrumentation of modest resolution. Typical spectral features include 254 nm emission from Hg, 388 and 420 nm emission from CN when organics are sampled, and 278 nm emission from M when chlorinated organics are sampled. We also observe several broadbands between 450 and 540 nm where uranium compounds are added to the D-B discharge region. We attribute this spectrum to electronic transitions of uranium oxide, probably UO. Additionally, we have used ANET to detect a number of heavy metals such as Cr, Se, Cd, Pb, and Cu. Dielectric-barrier (D-B) discharge technology generates the active nitrogen. This approach affords atmospheric-pressure operation, fluorescence excitation in gaseous, particulate, and aqueous sample matrices, and is amenable to field operation because the discharge and associated electronics are compact and can be powered by 12V batteries. This report details the results of the first phase of a three and a half year program designed to develop a portable monitor for sensitive hazardous waste detection. The ultimate goal of the program is to develop our concept to the prototype instrument level. In this first phase we have demonstrated the applicability of the ANET technology to a variety of hazardous species, and have determined detection sensitivity limits for Hg, Se, organics, and chlorinated organics to be at part-per-billion levels or below