Applications of Raman spectroscopy in forensic science. II: Analysis considerations, spectral interpretation, and examination of evidence

There have been several significant advances in Raman spectroscopy instrumentation during the past few decades, and this method is now a fully mature analytical technique on par with its counterpart, infrared spectroscopy. The latter method experienced a quantum leap in use in the forensic science laboratory following the introduction of inexpensive FT-IR spectrometers in the 1980s, but forensic scientists have been slower to embrace Raman spectroscopy. However, this promising technique is finally making some inroads into the forensic science laboratory, and to facilitate this process, this article presents a comprehensive review of Raman spectroscopy; it emphasizes how and why this underutilized method can be a very valuable tool for the analysis of a wide variety of evidentiary materials. Part I of this article described the principles of Raman spectroscopy, including theory, instrumentation, and a comparison of spectral data obtained using infrared and Raman methods for various analytes. Part II discusses how different analytical conditions can affect Raman spectra, and what bearing this and other factors may have on spectral interpretation; it also presents a review of the literature describing applications of Raman spectroscopy for the examination of various types of evidence.