Classification Of Blue Ballpoint Pen Inks And Blue Gel Pen Inks Using Chemometrics Methods

With the wide spread of ball-point pen and gel ink pen, it is becoming increasingly important for identification of ink handwritings in forensic science.Most of its application regard the detection and confirmation of alterations to documents with significant financial value(such as contracts,wills,insurance claims and so on).it is therefore evident that there is a great need for the establishment of a simple,accurate and effective method that will allow an in-depth examination of the inks used to produce a document.Chemometrics is a newly established mathematical method, which is widely used in statistical analysis of chemistry experiment datas.multivariate chemometrics is a powerful tool when dealing with multi-component systems and allows the extraction and compress of variables.In this paper, firstly, UV-vis spectrophotometry and High performance liquid chromatography were used respectively in analysing gel ink pens and blue ball-point pens, secondly, Principal component analysis(PCA) and Hierarchical clustering analysis(HCA) were used for the classification and identification of samples.Chapter one mainly introduce the advance of ink research and the principals and applications of Chemometrics methods.In chapter two, firstly, thity-three blue gel ink pens were analysed by UV-vis spectrophotometry, and classifications were achieved according to different peaks; secondly, Hierarchical clustering analysis and Principal component analysis(PCA)was also applied in analysis of samples.In chapter three, a High performance liquid chromatography (HPLC) method was established to study blue ball-point pen inks , different kinds of blue ball-point pen inks were classified into different categories according to flow chart; then, Using relative peak areas as variables ,Hierarchical clustering analysis(HCA) and Principal component analysis(PCA) was applied to identify different kinds of blue ball-point pens,in addition, a Non-aqueous capillary electrophoresis method was established to discriminate different kinds of blue ball-point pens.