Atypical deep eutectic solvents: New opportunities for chemical analysis

Over the past two decades, deep eutectic solvents have evolved from an interesting laboratory phenomenon to promising solvents widely used in many fields of science. Their unique physicochemical properties, ease of preparation and low toxicity have made them promising alternatives to traditional organic solvents and ionic liquids. However, most related research has focused on the use and study of a limited set of well-known deep eutectic solvents. This trend has led to the fact that new, "atypical" deep eutectic solvents have rarely been studied and introduced into chemical analysis. Consequently, the purpose of this review article is to shed light on the little-studied area of "atypical" deep eutectic solvents and to draw the attention of researchers to them for more detailed study and application to solve a wide range of analytical problems.