Volume 49, Issue 2 (March 2004)

    Differentiation of Black Gel Inks Using Optical and Chemical Techniques

    (Received 10 August 2003; accepted 8 November 2003)

    Published Online: February

    CODEN: JFSOAD

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    Abstract

    Gel ink pens have become a common writing instrument in the United States. Questioned document examiners often attempt to optically differentiate gel inks from each other and from other non-ballpoint ink writings (e.g., those from roller-ball pens). Since early formulations were primarily pigment-based, they do not elute when analyzed by thin-layer chromatography. However, recent gel ink formulations (i.e., within the past five years) include dye-based inks that can be easily separated. This study differentiates black gel inks using optical and chemical techniques. The techniques include: microscopy, visible and near infrared reflectance, near infrared luminescence, thin-layer chromatography (TLC), spot tests, and gas chromatography/mass spectrometry (GC/MS). As a result of this study a flow chart has been developed allowing for a systematic determination of a questioned ink. In addition, an analysis of volatile compounds found in gel inks revealed that there are some unique ingredients that may be found in gel inks that are not typically found in other non-ballpoint inks.


    Author Information:

    Cantu, AA
    Forensic Services Division, Washington, DC

    LaPorte, GM
    Forensic Services Division, Washington, DC

    Wilson, JD
    Forensic Services Division, Washington, DC


    Stock #: JFS2003262

    ISSN: 0022-1198

    DOI: 10.1520/JFS2003262

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    Author
    Title Differentiation of Black Gel Inks Using Optical and Chemical Techniques
    Symposium , 0000-00-00
    Committee E30