The solution is then
screened and analysed using mass spectrometry, which
involves an instrument that breaks up ions. These ions are
attracted into a magnetic field and when their charges
are measured in contrast to the mass of the ions, it identifies
the chemical composition of the solution.
Another method used
is thin-layer chromatography, which involves the liquid
sample being pushed in an upward direction by a specially
coated plate, using an organic solvent that soaks upwards
from the base. The different components in the liquid sample
move up at different speeds and separate onto a plate, which
then allows the solution to be identified.
A mass spectrometer/gas chromatograph is situated top left
and a thin layer chromatography plate is pictured at the bottom.
Photos are both courtesy of Lothian
and Borders Police Forensics Lab.