Forensic science ink analysis is one of the most traditional analytical fields. Currently, thin-layer and column chromatography as well as slab gel electrophoresis are used to investigate ink composition, but, recently, CZE has been tentatively applied, with encouraging results (Fanali and Schudel, 1991).
Reversed-polarity separations were carried out in a silica-coated capillary (200 mm X 25 mm i.d.) using 0.1 M ammonium acetate buffer (pH 4.5), with methanol (3:1). Detection was by UV absorbance at 206 nm. Commercially available fiber-tip pen inks were examined, and differences between the relative electrophoretic patterns from different inks were reported. Excellent peak shape and resolution of several components was observed, but quantitation was not attempted. In addition, dye spots separated by thin-layer chromatography were extracted and added to the same ink sample to check by analyte addition the identity of the well-resolved, but individually unknown CZE peaks.
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