Inks in the Analytical Laboratory: A Forensics Activity for Undergraduate Students

Here, we present a laboratory activity in which the studentsworkon an analysis of a questioned document that was written with oneout of five possible pens. As a forensics study, the activity appliedchemistry and analytical chemistry tools to solve the case. The studentswere able to apply polarity and solubility concepts to select anddiscard some pens. They also learned the basics of fluorescence andthe possibilities of using it to detect falsifications. Then, theywere able to set up the detection conditions for the HPLC-UV analysisby studying the absorbance behavior of the blue dyes. Finally, thestudents identified the pen used to write the suicide note and partiallycharacterized the composition of the ink. This multipurpose activityperfectly suits subjects involving analytical techniques and forensicsfor students with basic knowledge of chemistry that are studying instrumentaltechniques for the first time.