Natural Deep Eutectic Solvents as a Green Alternative for Extracting Contaminants from Food Samples: A Review

Abstract

Green Analytical Chemistry attempts to develop analytical procedures that reduce the environmental impact of the reagents and processes while also ensuring efficiency and cost-effectiveness. This Green Chemistry philosophy impacts the analysis of contaminants in foodstuffs, a global concern due to their harmful effects on human health. Most contaminant extraction methods are based on organic solvents, which are toxic to humans and hazardous to the environment. Thus, using novel green extraction solvents to replace the current ones is a huge challenge. In this sense, Natural Deep Eutectic Solvents (NADESs) are a great alternative. These solvents have been proven to behave similarly to traditional solvents (i.e., organic solvents and ionic liquids) in extracting and removing different contaminants from food samples. The synthesis of NADESs is simple and involves low-cost, environmentally friendly, and natural-origin constituents. Moreover, NADES-based extraction methods require fewer steps and reduce the risk for workers as milder experimental procedures are needed. Here, we review a critical gap in the literature: the application of NADESs in the extraction of food chemical contaminants. This review is relevant given the frequent combination of NADESs with organic solvents involved in sample preparation, a practice that confuses future users of this methodology and contradicts the basic principles of green chemistry. Following sustainable development objectives, avoiding these inconsistencies, and highlighting ecological methods to control contaminant residues in food samples are necessary. We believe this review will be a starting point for facilitating the implementation and commercialization of 100% green analytical methodologies applied to the food sector.