Herbicide Residue Analysis and Environmental Monitoring: Analytical Techniques, Challenges, and Future Perspectives

Herbicides are fundamental to contemporary agricultural production, playing a key role in effective weed suppression and yield improvement. Nevertheless, their extensive and sometimes indiscriminate application has raised growing concerns regarding environmental pollution and potential human health risks. In the context of integrated and sustainable weed management (ISWM), the ability to accurately detect and monitor herbicide residues is critical for improving application efficiency, reducing ecological burdens, and limiting the emergence of resistant weed species. This chapter presents a detailed examination of analytical techniques used for herbicide determination across diverse environmental and agricultural matrices, including soil, water, and food products. It covers well-established chromatographic methods such as gas chromatography–mass spectrometry (GC–MS), high-performance liquid chromatography (HPLC), and liquid chromatography–tandem mass spectrometry (LC–MS/MS), in addition to spectroscopic and electrochemical methodologies. Particular attention is given to recent technological advances, including nanostructured sensor systems, portable analytical instruments, microfluidic devices, and immunoassay-based platforms that facilitate rapid and in situ analysis. Relevant regulatory requirements and residue limits are also discussed in relation to environmental safety and compliance. Furthermore, the chapter critically addresses key analytical constraints, including matrix complexity, ultralow detection limits, signal interferences, and the identification of degradation and transformation products (TPs). Future directions emphasize the convergence of innovative analytical tools with sustainable weed management practices to enhance precision agriculture and promote environmentally sound decision-making.