A technique that uses the absorption of infrared radiation to produce a chemical fingerprint of a substance; can be used in conjunction with gas chromatography
Mass spectroscopy (MS)
A technique that uses molecular fragment (ion) patterns to produce a “chemical fingerprint” of a substance; can be used in conjunction with gas and liquid chromatography
Nuclear magnetic resonance spectroscopy (NMR)
A technique that monitors the splitting of nuclear energy levels within a molecule when it is exposed to oscillating magnetic fields
Raman spectroscopy
A technique that uses the inelastic scattering of light by matter to produce a chemical fingerprint of a substance
Category B: Moderately Specific Techniques
Technique
Description
Capillary electrophoresis (CE)
A separation technique using the differential movement or migration of ions by attraction or repulsion in an electric field through buffer-filled narrow-bore capillary columns as an identification tool
Gas chromatography (GC)
A separation technique that uses gas flowing through a coated tube to separate compounds by their size, weight, and chemical reactivity with the column coating
Liquid chromatography (LC)
A separation technique that uses liquid flowing through a coated tube to separate compounds by their size, weight, and chemical reactivity with the column coating
Microcrystalline tests
A technique that uses the microscopic crystals produced by chemical reactions to provide information regarding the identity of the substance being tested; a series of positive microcrystalline tests can be considered to be a conclusive test
Pharmaceutical identifiers
Comparing the physical characteristics of a commercially produced pharmaceutical product to known reference material to tentatively establish the composition of the preparation
Thin-layer chromatography (TLC)
A technique that uses solvents traveling through a porous medium to separate compounds by their chemical reactivity; can be documented through photographing or photocopying the developed thin-layer plate
Category C: Nonspecific Techniques
Technique
Description
Chemical color tests
A technique that uses the colors produced by chemical reactions to provide information regarding the structure of the substance being tested
Fluorescence spectroscopy
An analytical technique that uses the release characteristic wavelengths of radiation following the absorption of electromagnetic radiation (fluorescence) to establish a compound’s potential identity
Immunoassay
A laboratory technique that uses the binding between an antigen and its homologous antibody to identify and quantify the specific antigen or antibody in a sample
Melting point
The temperature at which a solid becomes a liquid at standard atmospheric pressure
Ultraviolet (UV) spectroscopy
A technique that uses the absorption of ultraviolet radiation to classify a substance
Reference: Forensic Science Book By Nordby, James, and Suzanne.
