Use of Raman spectroscopy and multivariate classification techniques for the differentiation of fingernails and toenails

The differentiation of fingernails and toenails using Raman spectroscopy and multivariate classification technique is discussed. Raman spectra of both fingernails and toenails were collected using a Renishaw InVia Reflex dispersive Raman microscope after the nail clippings were stored for a few days before Raman measurements were performed. The data were collected into one data matrix and preprocessed by adjacent 5-point smoothing to reduce noises, which was followed by background fluorescence subtraction using fifth-order modified polynomial fitting. The accuracy of the differentiation of toenails and fingernails by this classification method was found to be 75%. This method also proved to be quick, without requirement for much sample preparation.