Στο καινούργιο e-τευχος του Journal of Forensic Sciences International (Volume 52 Issue 5 Page 1205-1211, September 2007 ), οι Jamie D. Dunn και John Allison παρουσιάζουν μια εργασία με τίτλο: "The Detection of Multiply Charged Dyes Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for the Forensic Examination of Pen Ink Dyes Directly from Paper".
In the new Issue of Journal of Forensic Sciences I (Volume 52 Issue 5 Page 1205-1211, September 2007 ), Jamie D. Dunn & John Allison present a paper titled: "The Detection of Multiply Charged Dyes Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for the Forensic Examination of Pen Ink Dyes Directly from Paper".
Laser desorption mass spectrometry (LDMS) is emerging as a technique for questioned document examination. Its use is limited to detecting ink dyes that are neutral or singly charged. Several inks contain dyes that are multiply charged and LDMS cannot be employed for their identification. We have successfully detected >20 polyionic dyes that can be used in the manufacture of inks using matrix-assisted laser desorption/ionization (MALDI) MS, directly from paper, with the matrix, 2-(4-hydroxyphenylazo)benzoic acid (HABA), and the additive, diammonium hydrogen citrate (DAHC). For example, Acid Violet 49, a charged dye containing one positively-charged site and two negatively charged sulfonate groups, cannot be detected by LDMS, but forms intact, singly charged ions in the MALDI MS experiment. The method described is also useful for identifying multiply charged dye mixtures that are used in modern pen inks.
Journal of Forensic Sciences: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1556-4029.2007.00535.x
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