Forensic Chemistry
Objectives
Introduces calculations on drugs and alcohol
Defines the ‘drink driving’ legal limit
Highlights the importance of analytical measurements in forensic science
Explains the advantages of analysing hair for drugs.
Pre-requisites
The ideas which form the background to this unit are listed in the following table:
Topic Book page
Half-life 258
Organic chemistry (especially of alcohols) Unit 18, pp. 330–1
IR spectrum of ethanol 382–384
Chromatography 360–4
The scope of forensic chemistry
Forensic chemistry is the application of chemistry to the legal system. It includes the
analysis of unknown substances from the scene of a crime or from samples of body
tissue. Forensic chemistry uses the full range of analytical techniques available to the
chemist, as shown in Table 23.1.
Forensic Chemistry has strong links with forensic toxicology, the ‘science of poi-
sons’. Examples of molecules of interest to the forensic chemist are given in Figure
23.1.
23.2
23.1
Contents
23.1Pre-requisites 422
23.2The scope of
forensic chemistry 422
23.3Variation of the
concentration of a
poison with time 424
23.4Calculations using
first-order kinetics 424
23.5The zeroth-order
kinetics of ethanol
decay 425
23.6Drinking and
driving 426
23.7Analysis of drugs
in hair 428
22.7Revision questions 429
23
UNIT