Abstract:

Traces of 13 blue roller-ball pen inks were identified by high performance capillary electrophoresis (HPCE) with 0.03 mol/L borate and 10%(in volume) methanol as buffer at the voltage of 15 kV and the temperature of 25 ℃. Samples could be classified into 3 major groups and 5 subgroups by UV detection results and 4 species by visible detection results. The analytical results with different wavelength lights could be used to cross confirm the ink species. The aging effect was studied for 3 samples stored in darkness, and the relative ages were determined based on the relative quantities of some components. In addition, no effect of the matrix of paper was found on the results.

Key words: blue roller-ball pen inks, classification of writing inks, forensic identification , writing age, high performance capillary electrophoresis