Spectroelectrochemical sensing of chlorinated hydrocarbons for field screening and in situ monitoring applications.
Carrabba-MM; Edmonds-RB; Rauh-RD; Haas-JW III
NIOSH 1991 Feb; :67-72
The use of surface enhanced Raman spectrometry (SERS) for the detection and identification of chlorinated hydrocarbons or organochlorides such as carbon-tetrachloride (56235), 1,2- dichloroethane (107062), chloroform (67663), and trichloroethylene (79016) was described. The procedure was based on a photon induced electrochemical reaction which was detected by SERS on electrodes. Electrochemical methods were used to reduce the chlorinated organic solvents into reactive intermediates, which then reacted with a trapping reagent. SERS was then used to determine the chlorinated hydrocarbons. An optical fiber was used for excitation. The findings confirmed earlier studies which indicated that carbon- tetrachloride was not observable on silver substrates. Chlorinated hydrocarbons were not observable on silver or gold substrates, but SERS spectra were visible when they were examined with a copper electrode. Preliminary observation suggested that the SERS spectrum is only observable for a finite amount of time. The result is either due to the degradation of the electrode or the sample. The SERS on copper surfaces was a method which not only sensed the chlorinated hydrocarbons in a solution, but was also able to remove them from the solution.
Chemical-analysis; Environmental-pollution; Monitoring-systems; Chlorinated-hydrocarbons; Organo-chlorine-compounds; Spectrographic-analysis; Electrochemical-analysis;
56-23-5; 107-06-2; 67-66-3; 79-01-6;
Field Screening Methods for Hazardous Wastes and Toxic Chemicals. Second International Symposium, February 12-14, 1991. Sponsored by U.S. EPA; U.S. DOE; U.S. Army Toxic and Hazardous Materials Agency; U.S. Army Chemical Research Development and Engineering Center; U.S.A.F.; Florida State Univ.; National Environmental Technology Applications Corp.; and NIOSH