A new mutagenic compound has been isolated from ground beef which was fried at 300 degrees C for 5.5 min on each side. The new mutagen was purified using an aqueous acid extraction, XAD-2 adsorption-solvent elution, a series of preparative and analytical h.p.l.c. purification steps, and monitored with the Ames/Salmonella assay. This study reveals a new mutagen member of the amino-imidazoazaarene class of aromatic amines, having a mol. w of 224, and a formula of C13H12N4 as determined by high-resolution mass spectrometry. N.m.r. spectrometry supports the structure, 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP), for the new mutagen. The 1-methyl and 3-methyl synthesized isomers of PhIP were compared to the purified mutagen. The two isomers had identical mass spectra to the purified compound, but only the 1-methyl isomer showed similar u.v. and n.m.r. spectra. The two synthetic isomers were separable by h.p.l.c. and the beef derived component co-eluted with the 1-methyl-PhIP isomer. PhIP has a specific activity in the Ames/Salmonella assay of 1950 revertants/microgram. Although it is not as mutagenic as other compounds isolated from fried beef (e.g. MeIQx, 58 000 revertants/microgram) it is the most abundant mutagenic compound by mass in fried beef. PhIP is present at approximately 15 p.p.b. of the original weight of uncooked beef (accounting for 75% of the mass of genotoxic material) and contributes 18% of the total mutagenicity of the fried beef.

In the future, mediated electrochemical oxidation (MEO) may be used for the ambient temperature destruction of hazardous waste and for the conversion of mixed waste to low‐level radioactive waste. We have studied the MEO of ethylene glycol and benzene, two model compounds, in an electrochemical reactor. The reactor had a rotating‐cylinder anode that was operated well below the limiting current for Ag(II) generation. Rates of CO2 generation were measured and used to calculate both destruction and current efficiencies for the process. Gas chromatography with mass spectrometry (GC/MS) was used to identify several reaction intermediates. A simple model was developed to predict the time dependence of CO2 evolution.

A miniature, integrated chemical Iabaratory ().lChcmLab) is being developed that utilizes microfabrication to provide faster response, smaller size, lower power Operation, and an ability to utilize multiple analysis channels for enhanced versatility and chemical discrimination. Improved sensitivity and selectivity are achieved with three cascaded components: ( l) a sample collector/concentrator, (2) a gas chromatographic (GC) Separator, and (3) a chemically selective surface acoustic wave (SA W) array detector. Prototypes of all three components have been developed and demonstrated both individually and when integrated on a novel electrical and fluidic printed circuit board. A hand-held autonomaus system containing two analysis channels and all supporting electronics and user interfaces is currently being assembled and tested.

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In the future, mediated electrochemical oxidation (MEO) may be used for the ambient temperature destruction of hazardous waste and for the conversion of mixed waste to low-level radioactive waste. We have studied the Co(III)-mediated electrochemical oxidation of ethylene glycol, 1,3-dichloro-2-propanol, 2-monochloro-l-propanol, and isopropanol in sulfuric acid. The electrochemical reactor had a rotating cylinder anode that was operated well below the limiting current for Co(III) generation. Rates of CO:: generation were measured and used to calculate both destruction and current efficiencies for the process. We found that electrode separators can bc eliminated in MEO processes based upon Co(III) and sulfuric acid. Electrodes must be separated by ion exchange membranes in classical Ag(II)-based processes.