Ethidium bromide in water, TBE buffer, Mops buffer, and cesium chloride solution may be completely degraded by reaction with sodium nitrite and hypophosphorous acid. Only nonmutagenic reaction mixtures were produced. Destruction was >99.8% in all cases; the limit of detection was 0.5 pg ethidium bromide per milliliter of solution. Ethidium bromide also may be removed completely from the above solutions by using Amberlite XAD-I6 resin. The limit of detection was 0.05 pg ethidium bromide per milliliter of solution (0.27 &ml when cesium chloride solution was used). 0 1987 AC&& ~css IOC.
A simple one-step procedure for chemically degrading nitrosamine residues generated in the research laboratory is described. Treatment with aluminum-nickel alloy powder and aqueous alkali rapidly reduced all 11 nitrosamines studied to the corresponding amines. Hydrazines were produced as transitory intermediates, but these potential carcinogens were also easily reduced under the conditions employed, and no products except amines, ammonia, and, in some cases, alcohols were detected in the final reaction mixtures. Reduction proceeded smoothly in every other solvent system tested, except that reactions in acetone or dichloromethane solution were sometimes slow, incomplete, and/or led to unidentified products; therefore, we cannot recommend the procedure for use in these solvents. Otherwise, the method was efficient, reliable, and inexpensive and has been recommended as one of the preferred means of degrading potentially carcinogenic nitrosamines to innocuous products. Details of its application to some decontamination and disposal problems commonly encountered in the research laboratory are provided. Data illustrating this procedure's advantages over six other reducing systems are also presented.
The effect of moisture on the ability of a granular activated carbon to adsorb chloroform vapor from a flowing airstream was studied under three test conditions: (1) chloroform and water vapor were introduced concurrently into a dry carbon bed; (2) dry chloroform was introduced into a humidified carbon bed; (3) humidified chloroform was introduced into a carbon bed at the same relative humidity. The criterion for bed performance was the time when the downstream chloroform concentration was 1% of that in the inlet stream. Chloroform concentration was essentially constant at 108 +/- 2 micrograms/cm3; relative humidities (RH) varied from 0 to 97%. No RH effect on the adsorption of chloroform by the carbon was observed in test (1); tests (2) and (3) showed monotonic decreases in chloroform adsorption for RH greater than 40%. These results indicated that, for a dry carbon bed, the 1% breakthrough time for chloroform adsorbed from atmospheres of RH from 13% to 95% was essentially the same as that when RH = 0%. For humidified carbon beds, no change in 1% breakthrough time for chloroform was observed until RH was greater than 40%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.