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Applied Spectroscopy Online

Ink Forensics Lecture at the Society for Applied Spectroscopy (SAS) Chicago January 15, 2008 

When you sign your name on a piece of paper do you stop to think about what color the ink is or what is in it?  Ink is not merely one pigment or chemical.  It is a complex mixture. Ink pen companies do not reveal the identity of what chemicals are used in their inks.  Many crimes involve the use of forged documents, including forging checks.  Relevant analytical testing and data are needed to uncover this type of crime. Dr. Roger Jones of the Midwest Forensics Center at Iowa State University is one scientist trying to fight crime with his work in the laboratory. Dr. Jones spoke on Tuesday January 15, 2008 about the identification of ink chemicals for SAS-Chicago.  His talk was entitled “DART Mass Spectrometry for Ink Analysis.”

 There are many different brands and formulations of black and blue ink.  These many components in ink can be discovered with the use of mass spectrometry, which looks at the molecular weight of ions created in the gas phase.  Mass spectroscopy analysis is aided when ink solvents are not dissolved in solvent, and the sample is not processed, altered or destroyed.  Analysis gives higher quality results when only ink and paper are present. Ink on a piece of paper can be directly analyzed with a DART (direct analysis in real time) mass spectrometer with a time of flight detector.  Each ink sample provides evidence of the crime scene by helping investigators to identify the type of ink and brand name. The type of pen used, such as ballpoint, gel or fluid ink can also be identified. Dr. Jones and his colleagues are creating libraries of fresh and aged inks to fight crime.  Ink samples that are aged show a decrease in the peaks due to volatile components.  As a result time based measurements must be collected.
           
Dr. Jones also discussed how explosives, arson and drugs can be detected with mass spectrometry.  One of the most interesting aspects of the talk was that explosives can be detected on a suspect’s finger even after that finger has be touched or wiped off 52 times.  Mass spectrometry is one of the most powerful tools at our disposal in the fields of forensics and antiterrorism.
 
Wanda K. Hartmann
Freelance Writer
WKH Chem Consulting