Drugs: Analysis. Summary Analysis of Chemical Drugs Instrumental Examination Botanical...

Drugs: Analysis

Summary

Analysis of Chemical Drugs Instrumental Examination Botanical Examination

Chemical Examination

White Powder or Pills

What are they?

3 steps in processing unknown chemicals:

Screening step

Sample preparation step

Confirmatory test

Drugs > Chemical Exam

Color Test

Small amount of chemical in spot plate

Drop of color changing reagent added

Color change noted

Drugs > Chemical Exam > Screening

Color Test

Several tests done at same time.

Adulterants or diluents may affect color


Microcrystal Test

Small amount of sample dissolved in solution.

Test reagent added; contains another chemical that reacts with drug.

Insoluble crystal formed.


Microcrystal Test

Shape of crystal suggests type of drug.

Impurities may cause unusual crystal formation.


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


Different solvents result in different distances

Some systems include color change components

Thin Layer Chromatography (TLC)


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


UV Spectroscopy

Different drugs create a different pattern


Gas Chromatography

Similar to TLC; different chemicals will move at different rates through a capillary.


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.

Marijuana

Macroscopic Exam: Leaf and stem structure

Microscopic Exam: Tiny hairs on leaf surface

Drugs > Botanical Exam

Marijuana (Resin ID)

Color test:Tests for chemical THC

TLC:Tests for chemical THC


Peyote

Macroscopic Exam:Look for cotton-like tufts

Test for alkaloids:TLC & Gas chromatography

Confirming mescaline not necessary


Mushrooms

Macroscopic Exam:Can identify mushrooms that contain psilocybin

Screen for psilocybin:

Color test, TLC, and UV spectroscopy

Confirmed with MS and IR spec (later slides)


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.

Drugs

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

Drugs

Sample Preparation (Separation)

1. Physical Separation: particles are separated based on microscopic appearance.

2. Dry Wash or Dry Extraction

Dry Wash: Liquid dissolves adulterants; solid drug left behind

Dry Extraction: Liquid dissolves drug; solid adulterants left behind

Drugs > Sample Preparation

Sample Preparation (Separation)

3. Liquid/Liquid Extraction: Entire sample dissolved in aqueous (water)

liquid Organic liquid (oil-like) mixed with solution Organic liquid removes adulterants Sample remains in aqueous layer

Drugs > Sample Preparation

Confirmation Techniques

Confirmation identifies the specific type of drug.

Heroin?

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.

Drugs > Confirmation

Mass Spectroscopy


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.


Infrared Spectroscopy

Different drugs = different patterns Pattern is specific to one drug


Drugs: Analysis. Summary Analysis of Chemical Drugs Instrumental Examination Botanical...

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