Critical review of field-based forensics of chemical warfare agents in urban matrices: Integrating detection, sampling, and GC–MS identification in a deployable laboratory

Recent chemical incidents and the potential misuse of toxic agents in urban areas have renewed the need for rapid, reliable, and defensible field analysis. The forensic investigation of chemical warfare agents (CWAs) under such conditions remains highly challenging. This review critically examines strategies for field detection, sampling, sample preparation, and on-site laboratory identification of urban samples. Across air, liquid, solid, and polymeric matrices, analytical success depends more on sampling design and matrix-aware workflows than on instrumentation alone. Portable spectroscopic systems enable rapid field detection but rarely provide the level required for confirmed identification. GC–MS remains a key tool. Although many advanced laboratory protocols exist, most are impractical for mobile laboratories due to equipment constraints and time-critical conditions. Extraction remains a critical yet insufficiently optimized step. The review identifies these gaps as barriers to forensic validation and highlights the need for harmonized, matrix-specific workflows to strengthen future CWA field forensics.