Ternary Deep Eutectic Solvents in Analytical Chemistry: Design Principles, Sample-Preparation Strategies, and Emerging Sensing Applications

Abstract

In this review, we emphasize on ternary deep eutectic solvents (TDESs) utilized in environmental and analytical chemistry for separation and sensing purposes in contrast to their binary counterparts, known as simple deep eutectic solvents (DESs). To ensure food security, high water quality, and environmental protection from the current industrialized era of the twenty-first century, it is of utmost importance to determine and separate effluents, pollutants, or any undesired materials in our related day-to-day utilities, foods, or nature using a more efficient and green separating media or sensor. For this reason, there is no better choice for an analytical chemist to design and use hybrid and natural ternary deep eutectic solvents, with enhanced physicochemical properties. Since the discovery of simple binary DESs, they have been applied in sensing and separation sciences, but the invention of ternary deep eutectic solvents has made them a more interesting and suitable candidate for the development of separation or sensor methodologies based on TDESs. Furthermore, we explore TDES structure-property relationships, showing how the choice of components dictates macroscopic properties. This molecular-level understanding facilitates the rational design of tailored solvents for analytical applications. This review consolidates recent advances in TDES-based sensing and separation to support future research.