Document Detail

Photofading of ballpoint dyes studied on paper by LDI and MALDI MS.
MedLine Citation:
PMID:  16443368     Owner:  NLM     Status:  MEDLINE    
The determination of the age of an ink entry from a questioned document is often a major problem and a controversial issue in forensic sciences. Therefore, it is important to understand the aging process of the different components found in ink. The aim of this work is to characterize the degradation processes of methyl violet and ethyl violet, two typical ballpoint dyes by using laser desorption/ionization (LDI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), and to evaluate the possible application of the method to forensic examination of documents. The mass spectrometric methods were first tested and were found to be adequate for the purpose of this work. Moreover, it is possible to analyze the dye from a stroke directly from the paper (LDI-MS), so the sample preparation is minimized. The degradation of the dyes methyl violet and ethyl violet in strokes from a ballpoint pen was studied under laboratory conditions influenced by different factors such as light, wavelength of light, heat, and humidity. Then, strokes from the same ballpoint were aged naturally in the dark or under the influence of light over one year and then analyzed. The results show that the degradation of these dyes strongly depends on light fluence. Humidity also increases degradation, which can be explained by the basicity of the paper. The influence of heat on the degradation process was found to be rather weak. It was also observed that the dyes from the ink strokes did not show significant degradation after one year of storage in the dark. In conclusion, the storage conditions of a questioned document and the initial composition of the dyes in the ink have to be known for correct interpretation of the age of an ink entry. Measurements over longer periods of time are necessary to follow the degradation of dyes exempt from light exposure. LDI was found adequate and very useful for the analysis of ballpoint dyes directly from paper without further pretreatment.
Céline Weyermann; Dieter Kirsch; César Costa-Vera; Bernhard Spengler
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Publication Detail:
Type:  Journal Article     Date:  2006-01-27
Journal Detail:
Title:  Journal of the American Society for Mass Spectrometry     Volume:  17     ISSN:  1044-0305     ISO Abbreviation:  J. Am. Soc. Mass Spectrom.     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-02-28     Completed Date:  2006-06-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9010412     Medline TA:  J Am Soc Mass Spectrom     Country:  United States    
Other Details:
Languages:  eng     Pagination:  297-306     Citation Subset:  IM    
Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, Giessen, Germany.
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MeSH Terms
Coloring Agents / analysis*,  radiation effects
Forensic Sciences / methods*
Materials Testing / methods*
Spectrometry, Mass, Electrospray Ionization / methods*
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*
Reg. No./Substance:
0/Coloring Agents

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