Differentiation of Red and Black Ballpoint Pen Inks using High Performance Thin Layer Chromatography and Gas Chromatography-Mass Spectrometry

Abstract

The questioned document examiners usually encounter cases related to handwritten documents for the determination of their source, origin, and authenticity. The legal documents usually involve handwriting or signatures executed using ballpoint pens. These components of the ballpoint pen inks can be analysed, both qualitatively and quantitatively, using several techniques. The present study aimed to analyse the red and black ballpoint pen inks using high performance thin layer chromatography and gas chromatography-mass spectrometry techniques. All samples have been completely differentiated using high performance thin layer chromatography. The discrimination potential of gas chromatography-mass spectrometry for red and black ballpoint pen inks was found to be 32.85% and 63.58% respectively. Classification of inks has been performed in two levels, that is, primary differentiation on the grounds of major components of the ink and subsequent differentiation on the basis of minor components. The validity of technique was tested in terms of repeatability and reproducibility. Reproducibility has been determined by repeating the procedure of repeatability on different days. The results have been evaluated in terms of relative standard deviation (RSD), which is <2% for both repeatability and reproducibility.