Microextraction techniques for antibiotics surveillance in the food chain and environment

Antibiotics are commonly used to prevent and treat infections in human medicine, animal farming, and aquaculture. However, their excessive use can result in the development of antibiotic resistance and the presence of antibiotic residues in the food and environment. Therefore, it is essential to monitor antibiotic use and assess resistance, but the lack of standardisation and long-term quantitative data on antibiotic usage in different animal species is very challenging. Sample preparation techniques, such as solid-phase extraction (SPE) and liquid-liquid extraction (LLE), have been widely used, but they have limitations, including the need for large sample volumes, organic solvents, and complex and labourious protocols. Microextraction techniques (μExT) that align with the principles of Green Analytical Chemistry have gained attention in recent decades. Depending on the type of μExT used and the target analytes, the amounts of solvents, reagents, and samples used can be reduced by up to ten times or more. Often, the extraction time is also shortened by several orders of magnitude, labware requirements are much lower, and the analytical hardware can be simplified without compromising acceptable analytical performance. Notably, this includes the substitution of expensive LC-MS configurations with LC-UV or FLR cheaper equipment and detection systems. Greener solvents, such as ionic liquids (IL), supramolecular solvents (SUPRAS), and deep eutectic solvents (DES), have also been reported, further contributing to the development of more sustainable and environmentally friendly antibiotic extraction and analytical procedures. The AGREE tool metrics shows that substitution of conventional extraction approaches with μExT enables a greener profile for any methodology developed to analyse antibiotics in different food and environmental samples. This article provides a detailed overview of the advantages of using different μExT to monitor antibiotic usage in the food industry and environment and discusses the challenges and opportunities in this field.