Extraction is an essential step in an analytical protocol. Several techniques have been developed to achieve this step in practice: some are used on liquid matrices, others on solid matrices or gaseous matrices.
Extraction techniques were developed in the late 1980s, following a study conducted in several laboratories that brought to light the crucial nature of this step (Majors, 1991). Indeed, back then, the extraction phase represented about 60% of the time required to obtain an analytical result and was responsible for 30% of the error in the final result. Therefore, it seemed imperative to improve the practical implementation of this step.
Since the early 1990s, several techniques have come out. These developments have been made with two major objectives in mind: (i) to accelerate the extraction step, (ii) to automate this step to ensure a higher degree of reproducibility and to reduce the associated error. These developments very often aimed at a third objective: (iii) to limit the volumes of extractant (to reduce the use of potentially toxic solvents and to limit the dilution of the extract).