The other side of the paper as the evidence: impacts of fingermark development reagents on fingermark development and cocaine amount in cocaine-impregnated paper.

Despite various preventative measures, cocaine smuggling is still a major problem worldwide. A recent method of smuggling is the transportation of cocaine with various chemicals or with impregnated materials such as cloth and paper. This study aims to examine the change in the amount of cocaine on the paper surface and attempts to decide the best fingermark development method in the case of smuggling trafficking in the form of impregnated paper with the least effect on the cocaine concentration on the paper. The papers (n = 6 + 1) were prepared for each fingermark development method, including a blank paper, were dipped into a working solution prepared by dissolving 0.38 mg cocaine in 500 mL methanol. Fingermarks were developed by applying various chemicals, including Iodine vapor, 1,2-Indandione, DFO (1,8-diazafluoren-9-one), ThermaNin, 5-MTN (5-methylthioninhydrin), and silver nitrate chemicals and Ninhydrin, which is the most commonly used reagent for visualizing latent prints, particularly on paper surfaces. Also, the natural fingermarks of four different donors, two women and two men between 20 and 50 years of age, were used to compare with the presence of cocaine. Different from others, this study examined the application of DFO and 1,2-Indandione as alternatives to other chemicals and revealed that it is possible to identify cocaine using these methods. The order of success was Ninhydrin > DFO > 1,2-Indandione > ThermaNin > Iodine vapor = 5-MTN. To the best of our knowledge, the current study is the first to investigate fingermark identification methods along with the amounts of cocaine on cocaine-impregnated papers.