From “green” to “sustainable” sample preparation in the analysis of natural products: opportunities from new materials combined with microextraction techniques

The analysis of natural products and foodstuffs must cover a wide range of topics, from metabolomics studies to quality and safety controls. In all cases, sample preparation plays a fundamental role, as downstream analyses only detect the previously extracted metabolites. Therefore, the choice of the right extraction phase and technique is of utmost importance and the most critical parameter to be considered, also taking into account the complexity of plant and food samples. Most studies and official methods for these matrices still use traditional extraction techniques, which have a significant impact on the environment. However, the development of new and more environmentally friendly alternatives that are more in line with the principles of Green Analytical Chemistry has progressively increased in recent years. Strategies include the use of miniaturized techniques and new classes of more environmentally friendly extraction phases [1]. However, it is also important to remember that accurate and reliable measurements are required, especially for industrial quality control laboratories that have to deal with a variety of norms and quality standards to ensure safe products for the public, and that practical considerations such as productivity, cost and simplicity of methods should not be neglected [2]. This contribution explores the possibility of improving the environmental footprint of sample preparation while maintaining adequate analytical performance and laboratory productivity. This is done through a series of case studies dealing with the extraction of chemically diverse, specialized metabolites from natural products. A particular focus is on the use of renewable and tailorable materials in combination with technologies that enables to increase extraction kinetics, such as microwave-assisted extraction. In addition, the proposed methods are evaluated in terms of their overall performance using appropriate metric tools. The aim is to move towards “sustainable" analytical methods, where the improvement in terms of environmental impact is assessed together with productivity (which influences the economic aspect) and analytical performance, which should ensure high quality health products for all.