Overview and Orientation

In this chapter, we delve into the instrumental tools, techniques, and procedures utilized in forensic chemistry. The chapter is best thought of as akin to a ClijfsNotes of that enormous topic, a supplement to and summary of the many fine works listed in the References and Further Reading sections at the end of the chapter. For those who have recently taken an instrumental analysis course, much will be review for those who have not, enough information is provided to imderstand how and why the instruments are used and to understand information presented in the chapters that follow. Mass spectrometry and infrared spectrometry often are covered in an organic chemistry course, at least to the level of detail assumed here. The depth and breadth of each treatment corresponds to how widespread its application is in forensic chemistry. For example, inductively coupled plasma mass spectrometry (ICP-MS) was introduced in the mid 198(te and is routinely used in many materials, environmental, and research laboratories. However, it is rarely applied to forensic chemistry and hence is omitted here. Conversely, microscopy is a staple of forensic science and is not frequently used in other analytical settings. The presentation of each method is necessarily concise and is meant to provide information requisite to an understanding of later topics it is not meant as a replacement for an instrumental anal)reis course. 

The first forensic science laboratory, founded in 1910 by Edmrmd Locard, reportedly had two instruments a microscope and a spectrophotometer. The more things change, the more things remait the same Forensic chemists have many procedures and devices at their disposal, but their core instruments are 

The microscope has been associated with forensic science ever since Locard and Sherlock Holmes. The study of microscopy provides a foundation for study of spectroscopy. Simple microscopy is based on the interaction of visible light with matter, whereas spectroscopy is broadly defined as the interaction of electromagnetic energy with matter. Once visible light interacts with a sample, that light carries information about the physical and chemical characteristics of the sample. The same is true in all modes of spectroscopy. The detector in a microscope is the human eye and the characteristic that is most studied is color, but color is an expression of frequency and wavelength, characteristics exploited across the electromagnetic spectrum. 

In forensic science, UV/VIS and IR spectroscopy are the most rvidely used types of spectroscopy. X-ray techniques are employed for elemental and structural analysis, often as a complement to scanning electron microscopy (SEM). X-ray diffraction, used to examine crystal structures, is much less common. On 

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