Surface Enhanced Raman Scattering Spectroscopy (SERS) Analysis of Ink Pens in Forensic Usage

Abstract

ARTICLE INFO abstract The ink pens are very important in forensic questioned documents analysis in developing countries while the chances of fraud, manipulate documents and entry of the date of birth and death. In this mini review, fountain blue, red, green pen inks were used in the above-mentioned documents which have been discriminated by Raman spectroscopy (henceforth referred to as RS) and Surface-enhanced Raman scattering spectroscopy (henceforth referred to as SERS). RS is becoming major importance tool in forensic analysis because it is non-invasive, non-destructive analytical method allowed to sample examined without sample preparation. Raman spectra for different inks on questioned documents are measured at the uniform condition for all the samples. The spectral results are subjected to background correction and smoothening. The pre-processed spectral data are used for carrying out principle compound analysis (PCA). Through, the combination of RS and a statistical PCA method, we could able to differentiate among very similar ink types in the documents. Besides, the RS and PCA helped in identifying correctly the unknown ink pen. Moreover, the SERS was used to enhance the signals for less sensitive ink samples and quench the fluorescence effect. In this review we discuss about the electrodeposited copper on the pencil graphite surface as the SERS substrate for the forensic analysis of ink pens. This above-proposed method seems ease to make SERS substrate and low price which can be magnificently enhanced the plasmonic resonance effect. Hence, the substrate can also be used directly for a wide range of chemical and biological samples analysis not only for pen inks.