Attention given to the field of ionic liquids (ILs) has been increasing because of their potential uses as green solvent alternatives, due to their relative non-volatility, non-flammability, wide liquid range and high conductivity. However, first it is critical to know and understand their toxic effect on the environment. There have not been many studies that showed the relationship between the purity of the ILs and their toxic effects. A series of halide salts based on N-methylpyrrolidine was successfully prepared in different levels of purities determined by color and achieved by temperature variation. N-methylpyrrolidine was reacted with alkyl halides including 1-Bromobutane, 1-Bromopentane, 1-Bromodecane, 1-Bromododecane, and 1-Bromooctadecane to produce the corresponding quaternary ammonium halide salts. The structures of the salts were confirmed using H-1 and C-13 NMR spectroscopy. The salts were then converted to ionic liquids bearing the phosphate (PO₄^3-) and bis(trifluoromethylsulfonyl)imide (NTf₂) anions. Purity was also tested using fluorescence and UV Visible absorbance spectroscopy. This is a part of a larger collaborative research project where other similar series of ionic liquids were prepared and screened for their toxicity to a variety of microorganisms. Preliminary results indicate that bacterial growth inhibition caused by ILs is dependent on concentration, alkyl chain length and bacterial strain. B. subtilis appears to be more suitable for this type of analysis. It was also observed that alkyl chain length affects mycelial growth. This work was supported in part at BNL by the U.S. DOE Office of Basic Energy Sciences under contract # DE-AC02-98CH10886.