Classification Of The Red Ball-point Pen Ink

With the fast development of social economy, the case involved detecting and discriminating of distrustful document grows very year in forensic science and criminal reconnaissance. It is a big problem to examine the type and the dating of writing inks because of having too many ingredients and inaccurateness in measuring process. We tested 54 red ballpoint pens using 5 instrumental measures.Initially ,it was summarized the resent advance of questioned documents and dating writing inks and introduced some instrumental methods in common use including thin layer chromatography, gas chromatography, high performance liquid chromatography, capillary electrophoresis and high performance liquid chromatography-mass spectrometry. It was expounded the phylogeny, elements, configuration, class and component of red ballpoint Pen.54 red ballpoint pens were analyzed by ultraviolet-visible photography, electrochemical method, thin layer chromatography, high performance liquid chromatography and high performance liquid chromatography-mass spectrometry under the optimal experimental condition. Owing to HPLC greater sensitivity and resolving power, red ballpoint pens were separated into 6 kinds depending on numbers, reservation time and the most absorbing wavelength of chromatographic peaks in 350nm, 528nm.We had compared the signals and found the correlation of the 5 instrumental measures.The pens were categorized using other methods. Because of more peaks appearance in lower wavelength, we could classify red ballpoint pens better. A classifier flowchart was designed for more categorization depending on chromatographic peaks in 254nm. Every red ballpoint pen was distinguished with others on account of difference in quantity of ink components.