Comparative forensic discrimination of pink lipsticks using fourier transform infra-red and Raman spectroscopy

Abstract

As a routine, lipstick is daily used by females and can easily be transferred to clothes, cups, tissue papers, and other objects. The analysis of lipsticks is a relatively new and exciting field in forensics, helping to identify suspects in criminal cases where lipstick evidence has been left at crime scenes. By matching a specific brand of lipstick to a sample, investigators can positively connect certain individuals to locations or people, helping to aid in their investigation and subsequent proceedings. In this present study, 20 different pink shade lipsticks of the same manufacturer were analyzed using Vacuum FT-IR, and Raman spectroscopy to show a differentiation percentage of 95.8% between the samples. Data analysis using data mining techniques was performed on FT-IR spectra. Principle Component Analysis (PCA) was used as a data mining model for classification purposes, and it was able to distinguish between lipsticks samples based on their FT-IR spectra.