The applicability of ionic liquids (ILs) has been increased during the last years and even new opportunities are becoming a reality, for example mixtures of pure IL and inorganic salt as electrolytes for smart electrochemical devices. Some authors have stated the improvements of the properties of ILs after doping with a common anion inorganic salt (specially lithium salt). One of the most distinctive property of ILs is their negligible vapour pressure, since ILs are usually treated as “green solvents, although the high probability of a spill and filtration into aquatic environment lead us to perform deeper studies on ecotoxicity of these compounds.
In this work, the ecotoxicity of two protic ILs (Ethylammonium nitrate (EAN) and Ethylimidazolium nitrate (EIm NO3)) and one aprotic IL (butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C4C1pyrr TFSI)) doped with the corresponding Lithium salt (LiNO3,, for the protic ILs and LiTFSI for the aprotic IL) was tested towards changes on the bioluminescence of the bacteria Aliivibrio fischeri, using the Microtox® standard toxicity test. The effective concentration (EC50) of these mixtures was determined over three standard periods of time, namely 5, 15 and 30 min and compared with the corresponding values to pure ILs.
Results of EC50 at 15 minutes for these compounds, show pure EAN as the less toxic, meanwhile C4C1pyrr TFSI and EIm NO3 present slight toxicity. Addition of salt leads to interesting results, LiNO3 seems to induce to less toxic mixtures and LiTFSI provokes an increase on toxicity of the final compound.
