Forensic Drug Analysis 2/4/14

Screening and Confirmation Forensic Scientists determine the identity of drugs using… Screening Tests – preliminary tests used to reduce the # of possible identities of an unknown substance (color tests & microcrystalline tests) Confirmation – a single test that specifically identifies a substance.

Qualitative vs. Quantitative Identification of drugs may be… Qualitative – descriptive (An unknown sample may be determined to contain heroin and quinine.) Quantitative-amount (A sample may be determined to contain 10 % heroin and 90% quinine)

Color Tests Heroin Meth When mixed with a certain reagent, a drug can produce a characteristic color Useful for field investigators Screening tests only YouTube - Spray drug test kit for Cocaine residue detection Heroin Meth

Color Tests Marquis – heroin, morphine, opium derivatives (purple) amphetamines (orange-brown) Dille-Koppanyi-barbiturates (violet -blue) Duquenois-Levine – marijuana (purple) Van Urk – LSD (blue-purple) Scott test – cocaine (blue)

After color test… A more analytical test must be conducted to get rid of any false positives. These test could include: Chromatography –separate mixtures of drugs Spectrophotometer- shows how molecules are bonded