Systematic toxicological analysis in forensic and clinical laboratories: a challenging task of analytical chemistry

Abstract This lecture text presents the chemical analysis used for the investigation of a suspected poisoning in clinical and forensic toxicology. Following the discussion of the huge number and structural diversity of toxic substances, typical indications of a poisoning are given, which derive from the case history, the site where the unconscious person or the corpse was found, clinical symptoms, external examination of the corpse, or autopsy results. The different human sample materials, especially venous blood, urine, and gastric content, used for toxicological analysis are discussed with respect to their advantages, drawbacks, and special use. The strategy of systematic toxicology, to test for as much as possible poisons with a minimum of analytical procedures, consists of four main directions: (1) preliminary pretests and specific single or group tests (e.g., for alcohol, carbon monoxide, cyanide, the classic illicit drugs as well as for insulin, fluoride, and sulfide); (2) screening with inductively coupled plasma–optical emission spectroscopy (ICP-OES) or inductively coupled plasma–mass spectrometry (ICP-MS) for toxic metals and metalloids; (3) headspace gas chromatography (GC) in combination with MS in case of suffocation in a gas atmosphere or toxic action of volatile substances and solvent abuse; (4) sophisticated combinations of sample preparation, liquid chromatography (LC) with UV-diode array detection and GC or LC with different kinds of MS for toxic nonvolatile organic substances, i.e., the largest group of poisons including therapeutic and illicit drugs, pesticides and warfare agents, and plant and mushroom poisons. Explanations of these techniques, the toxic mechanisms, symptoms, and analytical findings are described on the basis of literature and the personal experience of the author.