High-performance liquid chromatography
High-performance liquid chromatography (Forensic Science)
Analysis by high-performance liquid chromatography (HPLC) begins with the injection of a liquid sample onto a chromatography column. The sample is then carried through the column by a high-pressure liquid solvent commonly referred to as the mobile phase. Because the individual pure compounds that are present in the sample have different chemical or physical properties, they travel through the column at different rates and exit the column at different times. Typically, the compounds are detected through the measurement of the absorption of a specific wavelength of ultraviolet light. However, the use of a diode array detector allows simultaneous measurement of absorption across the entire ultraviolet and visible spectra and thus is particularly useful for identification of unknown compounds.
An HPLC instrument, which consists of the injector, pump, column, and detector, consumes relatively large amounts of solvents. For this reason, HPLC is generally not a field-portable technique, so samples to be analyzed by HPLC must be carefully collected and handled prior to analysis. The analysis itself typically requires less than one hour, but often a good deal of sample preparation and method optimization must be done before the sample can be injected. The process must be conducted by a knowledgeable and experienced forensic chemist.
HPLC is particularly useful for the identification of drugs because of its ability to detect a small amount of...
(The entire section is 298 words.)
Further Reading (Forensic Science)
Bell, Suzanne. Forensic Chemistry. Upper Saddle River, N.J.: Pearson Prentice Hall, 2006.
Houck, Max M., and Jay A. Siegel. Fundamentals of Forensic Science. Burlington, Mass.: Elsevier Academic Press, 2006.
Skoog, Douglas A., F. James Holler, and Stanley R. Crouch. Principles of Instrumental Analysis. 6th ed. Belmont, Calif.: Thomson Brooks/Cole, 2007.
(The entire section is 49 words.)