Black Ball-point Pen Ink Types

As it is a frequently encountered problem of forensic science nowadays to distinguish whether the questioned documents, such as deeds, contracts and receipts, written in ballpoint pen inks are true or not, and identify the writing age of them, it is very essential to establish a simple, sensitive and accurate method to examine the similarities and differences of the ballpoint pen inks and identify the writing age. In this study, 130 different kinds of black ballpoint pen inks from different manufactures were studied, concerning five methods: UV-vis spectrophotometry, Oscillopolarography, High performance liquid chromatography, High performance liquid chromatogramphy-mass spectrometry and Hierarchical clustering analysisChapter one summarized the recent advance of the research to kinds and writing age of ballpoint pen inks.In chapter two, A High performance liquid chromatography (HPLC) method was established to study black ballpoint pen inks, different kinds of black ballpoint pen inks from different trademarks were classified into different categories according to disparities of their dye components. Hierarchical clustering analysis was adopted to analyze data of HPLC.In chapter three, High performance liquid chromatography-mass spectrometry (HPLC- MS) was used to studied black ballpoint pen inks.In chapter four, the kinds of black ballpoint pen inks were studied by UV-vis spectrophotometry, different UV absorption peaks were used for kind analysis.In chapter five, electrochemistry method was used to study the kinds of black ballpoint pen inks, different peak potentions were used for kind analysis.In chapter six, the research work of the dissertation was summarized and the prospect of this research field was given.