The Drug Chemistry
Section of the crime laboratory analyzes evidence for the presence of
cannabis and controlled substances as defined under the Illinois
Compiled Statutes, Chapter 720, Acts 550 and 570.
receives evidence for drug analysis in a variety of forms including
plant material, powders, liquids, tablets, capsules and paper. The most
common type of drug identified in the laboratory is cannabis (also known
as marijuana or pot). The second and third most common drugs identified
are cocaine and heroin respectively. Some other drugs commonly
encountered in the laboratory include hydrocodone/acetaminophen mixtures
benzodiazepines e.g. alprazolam (Xanax®), clonazepam (Klonopin®),
diazepam (Valium®); hallucinogens including lysergic acid
diethylamide (LSD), psilocin (found in “magic mushrooms”); ecstasy-type
drugs including 3,4-methylenedioxymethamphetamine (MDMA),
3,4-methylenedioxyamphetamine (MDA); anabolic steroids including
testosterone, stanozolol, nandrolone decanoate.
The drug analyst has
to first weigh the sample without packaging. This is achieved using an
electronic balance. Samples received in the laboratory can be as small
as a residue amount that is visible by eye, but not conducive to
weighing. They can also be very large. The laboratory has received on
occasion bales of cannabis (about the size of a microwave), and “bricks”
of cocaine (about the size of a hard-cover novel).
After weighing the
analyst then has to test the sample. At a minimum one preliminary test
and one confirmatory test has to be performed to be able to make
preliminary testing include color tests – wet chemical testing;
microcrystalline tests – using a polarizing light microscope (PLM);
ultraviolet-visible spectrophotometry – measuring the absorbance of
ultraviolet light by the sample dissolved in a liquid; thin layer
chromatography – separating components of a sample on a chemically
coated glass plate; gas chromatography – volatilizing a liquid
preparation of the sample and separating components of the sample.
Chromatograph-Mass spectrometer (GC-MS)
include mass spectrometry – breaking molecules into reproducible
and infrared spectrometry – measuring the degree of
transmission of infrared light through a sample. The data produced by
both of these methods is called a spectra and is akin to a chemical
fingerprint. For an unknown spectra to be identified as a controlled
substance it has to be compared to a known standard (purchased from a
chemical supplier, with a certificate of authenticity, that has been
verified in the laboratory by comparing its spectra to published data
before use in case work) run on the same instrument.
For cannabis in the
plant material form a microscopical confirmatory test can be performed.
This involves examining the unknown substance under a microscope and
observing for the presence of distinct morphological features.
On occasion the
section receives samples that despite thorough testing are not found to
contain a controlled substance. Some examples of commonly identified
non-controlled substances include baking soda, soap and vitamins.