Excellent site as entry point into an explanation with illustrations.
Forensic toxicology deals with the investigation of toxic substances, environmental chemicals or poisonous products.
For both alcohol and drugs, the most state-of-the-art analysis will involve spectrometry and often some form of chromatography.
An informational pamphlet by the Forensic Toxicology Council.
Discusses the various laboratory methods used in chemical toxicological analysis.
An overview from Toxicology Guide
Dr Linda Glowacki and Dr Jochen Beyer from the Victorian Institute of Forensic Medicine