Towards establishing a non-destructive technique for forensic ink analysis involving Raman spectroscopy with chemometric procedures

Abstract

Discrimination of ink is one of most challenging aspects in forensic science. Conversely, discrimination of inks had long been debated in the field, yet direct objective conclusion has been rarely achieved. Such a discrimination is nonetheless essential to provide explanations in term of variation in reproducibility or robustness. In this study, we demonstrated the capability of Raman spectroscopy (RS) coupled with Principal Component Analysis (PCA) for discrimination of gel pen inks. Based on the score plots of PC1 vs PC2, discrimination of 83.8% was achieved and 85.7% when PC1 vs PC2 vs PC3 were considered. As the application of chemometric techniques (PCA) to the forensic samples is a relatively new, but promising concept, further development for tasks relating to ink discrimination is recommended in this study for future work. Indeed, RS coupled with chemometrics would rapidly provide objective conclusion in forensic chemistry.