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Differentiation of Blue Ballpoint Pen Inks by Laser Desorption Ionization Mass Spectrometry and High‐Performance Thin‐Layer Chromatography
Author(s) -
Weyermann Céline,
Marquis Raymond,
Mazzella Williams,
Spengler Bernhard
Publication year - 2007
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2006.00303.x
Subject(s) - chromatography , inkwell , mass spectrometry , chemistry , desorption , thin layer chromatography , high performance thin layer chromatography , extraction (chemistry) , analytical chemistry (journal) , materials science , adsorption , organic chemistry , composite material
The differentiation of inks on a questioned document can highlight a fraudulent insertion and is usually carried out by optical comparison and thin‐layer chromatography (TLC). Laser desorption ionization mass spectrometry (LDI‐MS) may also be used for the analysis of dyes from ink. This analytical technique was compared with a standard method of high‐performance TLC (HPTLC) according to their capacity to differentiate blue ballpoint inks. Ink entries on paper from 31 blue ballpoint pens have been analyzed and their dye ink formulations compared. The pens were classified into 26 classes by LDI‐MS against 18 for HPTLC. LDI‐MS proved to be a more powerful method for differentiating ink formulations because it provides information about dye structures (molecular weights) and relative quantification of dye classes (peak areas). Sample preparation was minimal and analysis time was short in contrast to the more complex extraction, application, and development steps of the HPTLC method. However, only basic dyes and pigments were identified using positive mode LDI‐MS, while HPTLC did yield additional information about acid dyes.