Green sorbent-based microextraction techniques in sample preparation for food analysis

In food analysis, sample preparation is a crucial step of the analytical procedure due to the high complexity of the matrices, which cannot normally be directly analysed. Consequently, they must undergo a suitable sample preparation procedure involving a selective extraction procedure, as well as a clean-up of interfering matrix components, purification, and even preconcentration of the target analytes before instrumental analysis. However, conventional sample preparation procedures are often cumbersome, time-consuming and involve using large volumes of samples and solvents. Consequently, microextraction techniques have gradually gained attention in the food field and have been proposed to overcome these limitations and meet the Green Analytical Chemistry principles. Therefore, this chapter provides insights into these green sorbent-based microextraction techniques, including those that result from the miniaturisation of conventional methods (e.g. µ-SPE, µ-dSPE, µ-MSPD, µ-MSPE, and µ-QuEChERS), and describes those that have emerged as new microextraction formats (e.g. SPME, SBSE, PT-SPE, MEPS, and µSPEed) showing examples of their most relevant applications in the analysis of bioactive compounds and organic contaminants in food products over the last five years. Similarly, a section providing an overview of the main metric tools currently used to evaluate the greenness of the sample preparation procedures was included. The final section provides a summary with the main concluding remarks and directions for future research trends.