Powders, tablets, capsules, herbal materials and liquids which are suspected to contain controlled drugs are routinely submitted to forensic laboratories.
This section is intended to explain how these materials are examined and their ingredients identified, and how it is decided whether or not they contain controlled drugs.
The first stage in drugs analysis is to examine the submitted items and develop an analytical strategy. Most analytical techniques only require very small samples, so representative subsamples of the submitted material must be obtained. If the submission is a single bag of powder or a tablet, this is straightforward – it is homogenised and a subsample taken for analysis. If however the submission is large, a sampling strategy has to be applied.
This will typically involve sorting the material into types, which may include presumptive testing (see below), followed by application of a statistical sampling strategy to ensure that the subsamples analysed are representative of the whole.