An assessment of ionic liquid mutagenicity using the Ames Test

Recent interest in ionic liquids as green replacements for volatile organic solvents has led to an abundance of rapid toxicity testing to provide guidelines for safe designer engineering and synthesis. While toxicity tests have provided a wealth of information, no studies to our knowledge have investigated the mutagenicity of ionic liquids, which should be just as important for design guidelines. Here we present the results of the United States Environmental Protection Agency (US EPA) Ames Test for mutagenicity using Salmonella typhimurium strains TA98 and TA100 to ten ionic liquids. These include compounds with imidazolium, pyridinium and quaternary ammonium cations. Tests with these bacteria provide information on the ability of a chemical to cause frameshift and missense mutations, respectively, and can be related to higher organism carcinogenicity. Our test results indicated that none of the ten compounds tested met the US EPA criteria for mutagenicity. Two of the imidazolium cation ionic liquids indicated tendencies toward mutagenicity, but only at the highest doses.