Presumptive Color Tests in Forensic Analytical Toxicology

This chapter focuses on presumptive screening methods used in forensic analytical toxicology, particularly the role of color tests in identifying drugs and poisons. These tests are simple and cost-effective and offer quick results through visible color changes when a sample reacts with a reagent. While these tests are valuable in initial screenings, they are often non-specific and can yield false positives, requiring confirmation by more advanced techniques such as chromatography or spectrometry. The chapter outlines various color tests, including those for basic, acidic, and neutral poisons and highlights their application in screening for drugs, plant toxins, and inorganic poisons. Special attention is given to microcrystal tests for plant poisons, which identify poisons through characteristic crystal patterns. The chapter also covers the identification of gaseous poisons, snake and insect toxins, and mechanical poisons, which are used in criminal acts. It emphasizes practical considerations for performing tests, such as correct sample handling and environmental controls.