Green extraction techniques as advanced sample preparation approaches in biological, food, and environmental matrices: A review

Green extraction techniques (GreETs) emerged in the last decade as greener and sustainable alternatives to classical sample preparation procedures aiming to improve the selectivity and sensitivity of analytical methods, simultaneously reducing the deleterious side effects of classical extraction techniques (CETs) for both the operator and the environment. The implementation of improved processes that overcome the main constraints of classical methods in terms of efficiency and ability to minimize or eliminate the use and generation of harmful substances will promote more efficient use of energy and resources in close association with the principles supporting the concept of green chemistry. The current review aims to update the state of the art of some cutting-edge GreETs developed and implemented in recent years focusing on the improvement of the main analytical features, practical aspects, and relevant applications in the biological, food, and environmental fields. Approaches to improve and accelerate the extraction efficiency and to lower solvent consumption, including sorbent-based techniques, such as solid-phase microextraction (SPME) and fabric-phase sorbent extraction (FPSE), and solvent-based techniques (μQuEChERS; micro quick, easy, cheap, effective, rugged, and safe), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), in addition to supercritical fluid extraction (SFE) and pressurized solvent extraction (PSE), are highlighted.This research was funded by FCT (Fundação para a Ciência e a Tecnologia) through the CQM Base Fund, UIDB/00674/2020, Programmatic Fund, UIDP/00674/2020, and CEB—Centre of Biological Engineering, and by ARDITI (Agência Regional para o Desenvolvimento da Investigação Tecnologia e Inovação) through the project M1420-01-0145-FEDER-000005, Centro de Química da Madeira (CQM+; Madeira 14-20 Program). The authors also acknowledge FCT and the Madeira 14–20 Program to the Portuguese Mass Spectrometry Network (RNEM) through the PROEQUIPRAM program, M14-20 M1420-01-0145-FEDER-000008). ARDITI is also acknowledged for the postdoctoral fellowship granted to J.A.M.P. (Project M1420-09-5369-FSE-000001).