Matt Hickson, of LGC Forensics, has been a forensic drugs analyst for 10 years since completing his MSc in Forensic Science at King's College London. We spoke to him after his presentation for the Thames and Kennet group in early 2010.
You are obviously very enthusiastic about your work. What do you enjoy most about forensic drugs analysis?
MH: Well, I have been reporting evidence to court as an expert witness for over nine years, and I have worked on a number of high-profile cases, including several murders. I really enjoy going to court. But I am also an expert on drugs packaging, which can be a very rewarding part of the job.
Why do you look at the packaging?
MH: The materials used to pack illegal drugs can help us link batches together and help us to prove that a person caught with drugs is actually dealing. The minor imperfections in the way packaging is made are visible in the right lighting conditions. We use mechanical fit plus these imperfections to match up the drugs packages.
Is that the only way you can link drugs batches?
MH: No, our analysis will usually show up the chemical signature of the impurities in the confiscated sample, along with the banned substance. The impurities are added by the dealer to bulk up the drugs so they can make more money from a batch. The type of impurity used can link batches, and indicate where a batch has been cut. Typically, street cocaine is only 8-15% pure these days.
Your analysis sounds very sensitive. What do you use?
MH: Usually, we use gas chromatography linked to a mass spectrometer (GC/MS), but first we will carry out a presumptive test on any seized samples. The Marquis test, which is a simple spot-test to identify alkaloids and other compounds, still comes in very handy for this; it changes colour depending on the type of active drug involved.
And is this all the testing that you do?
MH: We have a wide range of tests available, such as HPLC (high performance liquid chromatography) and IR (infrared radiation), but to give evidence in court we need a positive presumptive test and a positive confirmatory test. Most often the Marquis and GC/MS test will provide this and prove very cost-effective.