Criminals beware! The smell of the money you are smuggling may give you in.
US researchers are developing a new device that mimics the function of trained dogs to sniff out large wads of cash moving illegally across the border.
Criminals smuggle an estimated USD 30 billion in US currency into Mexico each year from the US, researchers said.
The answer to the problem: a portable device that identifies specific vapours given off by US paper money.
In the past fiscal year, law enforcement officials say they uncovered more than USD 106 million in smuggled cash headed from the US to Mexico.
But this was only a small portion of the billions that made it across the border undetected - hidden among belongings, in clothing or elsewhere, said researchers.
"We're developing a device that mimics the function of trained dogs 'sniffing' out concealed money, but without the drawbacks, such as expensive training, sophisticated operators, down time and communication limitations," said Suiqiong Li of KWJ Engineering, a member of the research team.
"The system would extract gas samples from the traveller or from bags, vehicles and shipping containers. It would detect the trace currency emission signature even in the presence of car exhaust, perfumes, food and a range of temperatures, atmospheric pressures and relative humidity," said Li.
Li says the technique, known as the Bulk Currency Detection System (BCDS), should work effectively within the seconds or few minutes it takes for border inspections. It involves gas chromatography/mass spectrometry (GC/MS), a widely used analytical technique.
Experts already use this method for analysing vapours to detect drugs and explosives, as well as to investigate the causes of fires and identify unknown compounds.
But the current way to uncover smuggled money depends on checks by guards or trained dogs, without the benefit of any devices, according to Li.
The BCDS is being designed to find the emissions signature of the currency despite the presence of strong background gases and contaminants.
It would be an automated, hidden-money screening system, using GC/MS plus solid-phase micro-extraction and a thermal desorption technique. BCDS would automatically extract, preconcentrate and analyse the gases, Li said.
When developing the device, the researchers first had to figure out which gases money emits and how fast that happens.
It turned out that the gases are a set of trace chemicals, including aldehydes, furans and organic acids.
"We have found that US currency emits a wide range of volatile organic compounds that make up a possible 'fingerprint' that we can identify in less than a minute," said Joseph Stetter, principal investigator for the study, also from KWJ Engineering.
The research was presented at the National Meeting & Exposition of the American Chemical Society (ACS).