Essay On Raman Spectroscopy

1. Introduction

Fingerprints are one of the most important forms of physical evidence in criminal investigations and the most commonly used forensic evidence worldwide. Fingerprint examination cases typically match or outnumber all other forensic casework combined with approximately ten times as many cases solved using fingerprint evidence compared to DNA.1 Fingerprints are the patterns formed by raised papillary ridges on fingertips, which contain rows of pores that connect to sweat glands. After many years of research and study it has been established that papillary ridges on the fingers and palms of the hands, soles and toes of the feet, remain throughout life true to the mould in which they were fashioned by nature, unless their symmetry

But the disadvantage of Raman spectroscopy is that the weak Raman signals can easily be masked by fluorescence, either from the drug of abuse or the wide variety of adulterants/impurities encountered in samples, which may obscure Raman spectrum.2 Fluorescence interference can be reduced by using Raman spectrometer with an excitation wavelength in the UV or IR region. Raman spectroscopy does not require any sample preparation. The fingerprints remain unchanged by Raman analysis, allowing its subsequent use for the identification of an

The range of powders available for this purpose is extensive with the most commonly used powders consisting of Aluminum milled flake, or various grades of graphite and they are applied using glass fiber brushes specially constructed to minimize potential damage to the detail of latent fingerprint. The second group of powders used are magnetic powders. Application of these powders is via magnetic applicator. The advantage of magnetic powders is that there is no contact between the applicator and the fingerprint thus reducing the chance of damage that can be sustained to fingerprint. The powdered fingerprints are lifted using