Purity specification methods for ionic liquids

Abstract

In the last decade, ionic liquids have shown great promise in a plethora of applications. However, little attention has been paid to the characterisation of the purity of these fluids, which has ultimately led to non-reproducible data in the literature. In order to facilitate specification of ionic liquids, a number of analytical protocols with their limits of detection (where available) have been compiled, including methods of other authors. In particular, quantitative methods have been developed and summarised for the determination of the total ionic liquid content, residual unreacted ionic liquid starting material and by-products (amines, alkylating agents, inorganic halides), solvents from extraction procedures and water, in addition to decomposition products and total volatiles.