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Drugs: Analysis
Dr. Jason Linville
University of Alabama at Birmingham
[email protected]
Summary
Analysis of Chemical Drugs
 Instrumental Examination
 Botanical Examination

Chemical Examination
White Powder or Pills
What are they?
Chemical Examination
3 steps in processing unknown chemicals:

Screening step

Sample preparation step

Confirmatory test
Chemical Examination
Screening Test: Color Test

Small amount of
chemical in spot plate

Drop of color changing
reagent added

Color change noted
Chemical Examination
Screening Test: Color Test

Several tests done at
same time.

Adulterants or diluents
may affect color
Chemical Examination
Screening Test: Microcrystal Test

Small amount of sample
dissolved in solution.

Test reagent added;
contains another chemical
that reacts with drug.

Insoluble crystal formed.
Chemical Examination
Screening Test: Microcrystal Test

Shape of crystal suggests
type of drug.

Impurities may cause
unusual crystal formation.
Chemical Examination
Screening Test:
Thin Layer Chromatography (TLC)

Dot of drug placed at bottom
of paper or thin silica plate

Bottom dipped in solvent;
solvent diffuses up plate

Solvent carries drug up paper;
distance depends on drug
Chemical Examination
Screening Test:
Thin Layer Chromatography (TLC)

Different solvents result in
different distances

Some systems include
color change components
Chemical Examination
Screening with Instrumentation:
UV Spectroscopy



Sample dissolved in liquid;
placed in cuvette.
A range of UV light
wavelengths are passed
through solution.
Some light will pass through;
some light will be absorbed
Chemical Examination
Screening with Instrumentation:
UV Spectroscopy
Different drugs create a different pattern
Chemical Examination
Screening with Instrumentation:
Gas Chromatography

Similar to TLC; different chemicals will move at
different rates through a capillary.
Chemical Examination
Screening with Instrumentation:
Gas Chromatography

The time it takes to pass through the capillary
gives an indication of which drug it is.
Botanical Examination

With botanical evidence, additional steps
can be added to the screening process.
Botanical Examination
Marijuana

Macroscopic Exam:
Leaf and stem structure

Microscopic Exam:
Tiny hairs on leaf surface
Botanical Examination
Marijuana (Resin ID)

Color test:
Tests for chemical THC

TLC:
Tests for chemical THC
Botanical Examination
Peyote

Macroscopic Exam:
Look for cotton-like tufts

Test for alkaloids:
TLC and Gas chromatography

Confirming mescaline not necessary
Botanical Examination
Mushrooms

Macroscopic Exam:
Can identify mushrooms that
might contain psilocybin

Screen for psilocybin:
Color test, TLC, and UV spectroscopy

Confirmed with MS and IR spec (later slides)
Chemical Examination
Screening Summary

All screening tests give an indication of
what the drug is.

Since some drugs behave alike during
screening tests, confirmation of the drug
type is needed.
Chemical Examination
Sample Preparation

In many cases, the identity of the drug
must be confirmed for prosecution.

Before identification, it must be separated
from other chemicals in the mixture
Chemical Examination
Sample Preparation (Separation)
Physical Separation: particles are separated
1.
based on microscopic appearance.
Dry Wash or Dry Extraction
2.


Dry Wash: Liquid dissolves adulterants;
solid drug left behind
Dry Extraction: Liquid dissolves drug;
solid adulterants left behind
Chemical Examination
Sample Preparation (Separation)
Liquid/Liquid Extraction:
3.




Entire sample dissolved in aqueous (water)
liquid
Organic liquid (oil-like) mixed with solution
Organic liquid removes adulterants
Sample remains in aqueous layer
Confirmation Techniques
Heroin
Confirmation identifies the specific type of drug.
Confirmation Techniques
?
Confirmation identifies the specific type of drug.
Confirmation Techniques
Confirmation (Mass Spectroscopy)

MS will smash a molecule into pieces
and measure the mass of the pieces.

Every drug will break in a unique way,
creating a unique amount of pieces.
Confirmation Techniques
Confirmation (Mass Spectroscopy)
Confirmation Techniques
Confirmation (Infrared Spectroscopy)

Similar to UV spectroscopy, except a
range of infrared light wavelengths are
passed through a sample.

Some light passes through; some light
is absorbed.
Confirmation Techniques
Confirmation (Infrared Spectroscopy)


Different drugs = different patterns
Pattern is specific to one drug