Characterization and profiling of security inks and materials in international banknotes using ATR-FTIR spectroscopy coupled with chemometrics

Purpose This study aims to characterize key components of banknotes such as security inks, substrate paper and security threads from 12 different countries using spectroscopic and chemometric approaches. Design/methodology/approach Banknotes belonging to the countries India, China, Bangladesh, Russia, the UK, EU, the USA, Australia, Indonesia, South Africa and the UAE have been examined. Attenuated total reflectance-Fourier transform infrared spectroscopy, in conjunction with multivariate chemometric techniques, was used to evaluate chemical composition, identify patterns of similarity and discriminate between different banknotes. Findings Spectral profiling revealed the presence of materials such as cellulose, calcium carbonate, kaolinite, dialdehyde starch and oxime-based compounds. Two main types of security threads were identified: demetallized threads exhibiting high signal-to-noise ratios and acrylic polymer-based plastic threads. Among all…