## 4 Conclusions and Future Outlooks  
Sample preparation is a crucial step in any analytical method involving the determination of contaminants in complex samples, such as food and feed. In this sense, although SPE is still the sample preparation technique of choice for the extraction and purification of PAs, the QuECHERS method can be a suitable alternative, as it simultaneously performs multiresidue extraction and clean-up procedures. This strategy, besides allowing for the determination of multiple analytes at the same time, has proven to be faster, simpler, cheaper and more environmentally friendly than conventional SPE, providing the same or even better extraction efficiency than this sample preparation technique. However, in the last years, the QuECHERS method has scarcely been applied to the determination of PAs. Nonetheless, due to its inherent multiple advantages and its high throughput efficiency, its application in the determination of PAs is expected to increase significantly in the forthcoming years. Moreover, the requirement established in the recent PAs legislation to carry out multiresidue analytical methods will probably contribute to this increase. Conversely, due to the great flexibility of the QuECHERS method, it has been possible to improve and adapt its applicability to different analytes and matrices other than those initially designed in its origin, such as its application to the determination of PAs in a widevariety of food and feed samples. As it has been described, it is possible to introduce a large number of modifications in its key parameters to improve the extraction efficiency of the method depending on the sample and the analytes. In this sense, there is a wide variety of extraction solvents and clean-up sorbents that can be used individually or in combination, leading to endless options to optimize the method and achieve satisfactory results. Moreover, it has been observed that many of the works published that performed the QuECHERS extraction for the determination of PAs in food and feed samples also carried out at the same time the co-analysis of other contaminants, mainly plant toxins, pesticides, mycotoxins, drugs and phytoestrogens, with high extraction efficiency. This is interesting, as this strategy provides enough potential to monitor simultaneously in a single extraction the occurrence of different types of organic contaminants belonging to different chemical families, which involves a great advance and improvement in the food safety field. Finally, it has been proven that it is possible to carry out the miniaturization of the QuECHERS procedure, achieving satisfactory results in the determination of PAs. Several works have demonstrated that it is possible to reduce the amounts of sample, organic solvents and partitioning salts employed without losing extraction efficiency. These features enable great reduction in time, costs and wastes, leading to the development of improved cost-effective and environmentally friendly analytical methodologies that comply with the current GAC principles. Therefore, this opens a huge research window in the coming years to focus on the development of miniaturized strategies that increase the number of analytes to be extracted and extend their applicability to other food matrices with the aim of contributing to ensure the food safety of consumers. Conceptualization, I.S. and S.M.-Z. ; methodology, N.C.; software, N.C.; formal analysis, N.C.; investigation, N.C.; resources, I.S. ; data curation, N.C.; writing--original draft preparation, N.C.; writing--review and editing, N.C., S.M.-Z. and I.S. ; visualization, I.S. and S.M.-Z. ; supervision, I.S. and S.M.-Z. ; project administration, I.S. ; funding acquisition, I.S. All authors have read and agreed to the published version of the manuscript. This research was funded by MCIU/AEI/FEDER, UE, project number RTI2018-094558-B-I00. Not applicable. The authors declare no conflict of interest.