The city of Cusco, located in southeastern Peru, is famous for many reasons. It’s the site of the historic capital of the Inca Empire, a UNESCO World Heritage Site, and is currently the most important tourist destination in Peru, as it hosts nearly two million visitors each year. However, Cusco is also known for counterfeit currency.
Counterfeit Nuevos Soles (the Peruvian currency) are common and difficult to detect, especially for foreign tourists who are not as familiar with the currency. I’ve had my own experience with fake bills in the Cusco region. On a day trip to Machu Picchu in 2012, I bought a pair of silver earrings at a local craft fair (of course I checked them later with X-ray fluorescence to make sure they were real silver!). I only had large bills from the ATM, so I got change for the purchase. Later, when I tried to use the change to buy food at a soccer game, I was told that the bills were fake! I asked a local friend to show me the difference between the fake bill and a real bill because they looked identical to my eye. Even with his help, I still couldn’t tell the difference.
Researchers at the premier university in Cusco, Universidad Nacional de San Antonio Abad del Cusco (UNSAAC), have recognized that the proliferation of fake bills is a major threat to the tourism-focused economy of the region. In a collaboration between the departments of Physics and Chemistry, three researchers used X-ray fluorescence (XRF) technology to examine seven 200 Nuevos Soles banknotes, three of which were fake.
In their study, the UNSAAC researchers used our DELTA® Premium XRF analyzer (now updated to our Vanta™ XRF analyzer) to analyze 11 points on the seven bills. They performed two types of analyses: the first based on a fingerprint spectral comparison, and the second based on the chemistry of the bills. The team concluded that it was possible to distinguish between genuine and fake banknotes using XRF because the fake bills showed a different chemical makeup from the genuine banknotes. They also discovered that XRF could indicate which security marks are the most difficult to falsify. In addition, some fake banknotes also had trace amounts of toxic elements like lead, arsenic, and chromium, with two notes having chromium concentrations above limits allowed in toys according to Peruvian law. With fake banknotes comprising an estimated 0.5% of all bills in Peru, the UNSAAC team’s findings will help federal officials in removing the counterfeit banknotes from circulation.
Counterfeit currency is a serious problem not only in Peru but around the world. Recent technological developments have made the production of fake money relatively easy, and the influx of forged bills has reduced the value of
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