Sample preparation techniques for quality evaluation and safety control of medicinal and edible plants: Overview, advances, applications, and future perspectives

Medicinal and edible plants (MEPs) have attracted increasing interest worldwide due to their natural origin, reliable efficacy, and minimal side effects in recent years. However, the complex and fluctuating levels of inherent chemical constituents and exogenous hazardous contaminants have triggered widespread concerns about their efficacy and safety. Developing analytical methods for both active components and exogenous contaminants concealed in these samples is central to the quality evaluation, in which sample preparation is crucial. This paper systematically reviewed the evolution of standard sample preparation methods, microextraction techniques based on novel solvents and nanomaterials, and innovative integrated techniques from 2019. Accordingly, their merits and weaknesses were discussed by showing fruitful applications in identifying and quantifying active components in these plants. Further, successful applications for analyzing exogenous contaminants were prominently showcased, highlighting the management of pesticides, heavy metals, mycotoxins, and polycyclic aromatic hydrocarbons. Finally, forthcoming trends in sample preparation techniques were delineated to illuminate the development and implementation of more advanced sample preparation technologies.