Spectroscopic and Chromatographic Analysis of Pen Ink
To determine the color and composition of pen inks and inked writing found on documents pertinent to the case.
Collect a variety of ballpoint and felt tip pens and prepare documents with those pens. Assign pens and documents to the suspects and to the crime scene.
Extraction fluid and mobile phase: aqueous 0.005 M heptanesulfonic acid and acetonitrile mixed in 45:55 ratio.
Standard Reference Material
Visible spectrophotometry; liquid chromatography
UV-Vis spectrophotometer; pair of small-volume, 1-cm cuvettes; liquid chromatograph with C18 column and diode array detector; 2-mL chromatography vials with screw caps