Análisis químico forense de alteración de documentos en papel moneda basados en los casos del mercado central de Machala

Abstract

Counterfeiting and fraud are deceptive practices that negatively affect people and institutions. Paper currency documents have unique features that make them difficult to counterfeit, such as watermarks, security threads, and special inks. However, counterfeiters use various techniques to alter authentic banknotes, such as chemical erasure, banknote laundering, reprinting, and modifying serial numbers. Several historical and contemporary cases of banknote counterfeiting are presented, highlighting the complexity and impact of these crimes on the economy and public safety. Additionally, the ethical considerations and analytical methods used in forensic chemical expertise to detect alterations in paper currency are detailed, including spectroscopy, chromatography, and chemical testing. In this study, a descriptive and cross-sectional approach was used to investigate alterations in paper currency due to fraudulent manipulation. Counterfeit and authentic $5, $10, and $20 bills were collected. Data were collected in the central market of Machala and physical, chemical and instrumental analyzes were performed. Methods include macroscopic observation, drop assays (iodine, alcohol, water), microscopy, UV light and near-infrared spectroscopy. The results are compared to authentic banknotes to detect alterations, this study provides a detailed view of the effects of fraudulent manipulation on paper currency. Methods such as iodization, alcohol analysis, and microscopic examination revealed distinctive differences, such as ink resistance and paper composition. Additionally, microscopy and spectroscopy showed consistent discrepancies in security features between authentic and counterfeit banknotes. These findings highlight the importance of implementing broader strategies to mitigate economic losses and strengthen preventive measures against banknote counterfeiting.