1. ID, Collection of Evidence
9.4 Notes
ID, Collection of Evidence

2. Objectives
Describe the laboratory tests normally used to perform a routine drug identification analysis
Understand proper collection and preservation of drug evidence

3. Drug Identification Either a specimen is a specific drug or it is not
Chemists must be prepared to support and defend the validity of the results in a court of law
Screening test – reduces possibilities
first test is color test
Confirmation test - pinpointing

4. Drug Identification cont.
The procedures must be able to confirm that the likelihood of any other substance responding in an identical manner to a certain drug is so minimal that there exists no other conclusion but reasonable scientific certainty

5. Analytical schemes Color tests Microcrystalline tests Chromatography
Spectrophotometry
Mass Spectrometry

6. Color Tests
1. Marquis reagent – purple with heroine and morphine; orange with amphetamines
2. Dillie-Koppanyi – violet blue with barbiturates
3. Duquenois-Levine – ABC layers with layer C purple with marijuana
4. Van Urk – purple/blue with LSD
5. Scott Test – ABC (A with cocaine, blue to pink in B, and blue again in C layer)

8. Microcrystalline Tests
Chemical reagent added to drug on slide
Crystalline precipitate with unique structures results

10. Chromatography Uses TLC (Thin Layer Chromatography) and gas
Requires the Rf comparison of known and questioned drugs
Accompanies color and crystal test

11. Spectrophotometry
Absorption of light in the UV and IR regions of the spectrum
Establishes probable drug
IR can specifically ID a substance

12. Mass Spectrometry GC/MS
Utilizes the fragmentation pattern of sample molecules which serves as a fingerprint
Can be used to separate components of a complex drug mix

13. ID of Marijuana Based on botanical features
Cystolithic hairs – short hairs, shaped like bear claws
DuQuenois-Levine color test
Without leaf, TLC is used

14. Collection & Preservation of Drug Evidence
Original container
Airtight container if glue sniffing
Packages marked
Background information