14 DAY TRIAL // One of the most interesting and recently used methods of counterfeiting US dollars is to bleach the ink off the $5 bills and to print them with as $100 bills. The Treasury has only recently considered redesigning those bills to prevent the sudden "multiplication" of Ben Franklin.
A new technique has now been created and has been seen on the popular crime show "CSI: New York". It's called Direct Analysis in Real Time and it's a mass spectrometry interface designed to create a massive database containing ink mass spectra at it will use samples from the US Secret Service, which deals with counterfeit money.
This method will hopefully put an end to what the Central Bank of Ireland once called "the involuntary privatisation of banknote printing", by allowing federal agents to rapidly match the ink from newly appeared fake money with that of previously recorded cases.
The DART was developed by scientists at the Midwest Forensics Resource Center at Iowa State University and was designed to analyze ink by creating a stream of warm gas containing excited-state helium atoms or nitrogen molecules in the DART source.
When pointed at an ink sample, the gas and the species, which is in an excited state, evaporate, thus ionizing the molecules of the sample. These are then measured to create mass spectrum data for each ink sample tested.
"The great thing about the DART system is that it can sample the ink straight off the paper. You don't have to extract a sample first. Before DART, we had to cut a little bit of sample out and dissolve it in solvent for analysis. So, now we can look at the document without visibly altering it, which is good for forensic science. We don't destroy the evidence," explains Roger Jones, U.S Department of Energy's Ames Laboratory associate chemist.
This will greatly bring benefits to forensic detectives and Secret Service agents who will need much less time to complete the analysis and accurately say which batch of money the latest bills come from or if they are new products.
"We would have been satisfied with the mass spectra looking basically like the spectra obtained by the old extraction mass spectrometry methods, because the DART system still gets around damaging the sample and reduces the work involved in analysis," said Jones, "Time constraints are the major complaint of every forensic scientist. Their caseloads are so large that they just don't have the time to do traditional ink analysis."
The finished library of mass spectra will be made of more than 8,000 inks the Secret Service has compiled during their investigations and will allow them to stop the spreading of counterfeit money and to get to the distributors and the sources much easier.