A pocket-sized detector that can instantly spot traces of illicit drugs could be on the way. It would make life tougher for drug dealers by letting police confirm immediately which drugs, if any, a person has handled.
At the moment, drugs and forensic evidence from drug busts have to be sent to approved labs for analysis if the results are to stand up in court. For rough, on-site testing, police use sniffer dogs and 鈥渋on scans鈥�. Ion scanners are around the size of a small fridge, says Chris Lennard from the Australian Federal Police forensic laboratory in Canberra. Drug samples are put in a cell in the ion scanner and vaporised. The time it takes for the particles to drift from one end of a cell to the other identifies the drug, he says.
Simon Lewis and colleagues at Deakin University in Geelong near Melbourne set out to create a pocket-sized drug detector for people with no lab training.
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鈥淪uppose I鈥檝e got an empty bag here and I want to know, did it ever contain drugs?鈥� says Lewis. You just take a swab from the bag and mix it with deionised water in a vial. You then fill a second vial with a solution of a metal complex that varies according to the drug you suspect might be there.
The two vials are slotted into holes in Lewis鈥檚 detector where the liquids from each vial are mixed in precise quantities. As they mix, a reaction between the drug and metal complex produces a brief flash of light. A light sensor identifies the drug by measuring the intensity, wavelength and duration of the flash, says Deakin.
Confusing answers?
In a test, Lewis used a compound called ruthenium metal complex to look for the common analgesic drug codeine. He found he could detect 6 micrograms of the drug in a litre. 鈥淚t鈥檚 like being able to taste a crushed Tic Tac in an Olympic-sized swimming pool,鈥� he says.
By choosing specific metal complexes that react with different drugs to produce light, the system could quickly distinguish between hard drugs like cocaine and more innocuous substances, says Lewis.
Zoran Skopec, director of the Australian Forensic Drug Laboratory in Sydney, is interested in Lewis鈥檚 device but wonders how well it would fare if there was a mixture of drugs. 鈥淔ield kits like this might work with well-established chemicals,鈥� he says. 鈥淏ut new drugs or particular mixes often give a number of confusing answers.鈥�
Lewis agrees that mixtures can be difficult to identify. 鈥淭hat鈥檚 what we鈥檙e working towards,鈥� he says.