Statistical discrimination of black ballpoint pen inks using ultra-performance liquid chromatography with principal component analysis

Abstract

The aim of this study is to propose an approach for the analysis of black ballpoint pen writing inks based on ultra-performance liquid chromatography (UPLC) combined with principal component analysis (PCA). A total of twelve varieties of black ballpoint pens available in the Malaysian market were examined by an UPLC that coupled with a photodiode array detection (PDA). Chromatograms of ink samples were extracted at 279, 370 and 400 nm. Chromatographic data obtained were subjected to PCA after normalization. Seven principal components were produced from a total of 15 raw peaks. The new set of variables was then used for running one-way ANOVA to differentiate 66 pen-pair formed from twelve varieties of black ballpoint pen. The approach proposed here has successfully differentiated all pen-pair thus achieving 100% discrimination power.