Multi-component Chemometric Classification Of Ink

In the field of analytical chemistry, chemometrics is a robust method of analysis and discrimination. Thereinto, principal component analysis(PCA), hierarchical cluster analysis(HCA), linear discriminant analysis(LDA) are the preliminary methods for analysis and discrimination. PCA extracts the most useful information from the spectrum, reducing the variables analysed; HCA and LDA are effective method for discrimination.Applying the chemometrics methods to analyzing and differentiating inks is a effective means. The fingerprint chromatography (FPC) is a kind of quality control technology, the complexity and correlation of traditional Chinese medicine can be showed in the FPC, just like the human being's fingerprint. It is one of the key parts in the modernization of traditional Chinese medicine. Recently, with the development of modern analytical techniques and information science, FPC has been taken as the most effective method on the quality control of traditional Chinese medicine. The ink is a admixture with its composition complicated.Its main components include solvents, dyes/ pigments,resins,surfactants,humid-defending agents and so on.In the second chapter of the present study, Seventy-three blue ball-point pen inks of different brands were examined on the basis of the Vis spectrum of their methanolic solutions with a view to achieving good discrimination between them. Samples were dissolved in absolute methanol and their absorbance values in the range of 300～700nm,after appropriate transformations,were used as variables in the multivariate statistical techniques of principal component analysis(PCA) and hierarchical cluster analysis(HCA).These techniques were used successively so that an effective and meaningful cluster was achieved.The initial 201 variables(log10 transformed ink absorption values at each wavelength) were subjected to a PCA over the samples and only 6 variables were retained.After the PCA result and the component loadings were subjected to HCA ,it was found that 10 clusters was achieved on the basis of differences in the shape of absorption bands as well as their relative intensities, and that the result was accordance with that from 201 variables.So,the method can be used to classify and differentiate blue ball-point pens.In the third and the fourth chapter,applying the same methods as the above chapter redand black ball-point pens are analysed and discriminated .Red ones are classified into 10 clusters, ,and the black ones six clusters.In the last chapter, the fingerprint peaks of seventy-one black water-soluble inks of different brands are made out on the basis of the eletrophoresis grams,and compared .Firstly, the peak times of each electrophoresis grams are corrected ;secondly,choose the fingerprint peaks of each brand of water-soluble ink.Then the times of fingerprint peaks were subjected to HCA ,it was found that 14 clusters was achieved.