Criminalists in the toxicology unit are normally holders of B.S. to Ph.D. degrees in a physical science (forensic science, chemistry, biology, biochemistry, pharmacology).  These highly trained scientists examine blood, urine and/or other bodily fluids or tissues for the presence or absence of drugs and/or poisons.  Instrumentation used by these scientists include highly sensitive gas chromatograph mass spectrophotometers, liquid chromatography, fluorescent polarization immunoassay technology, and head-space gas chromatography.