lecture 1 - basic forensic analysis Flashcards
what should you do before colour/spot tests?
analyse the physical characteristics of the drug
What is the purpose of presumptive/spot tests in drug analysis?
To provide tentative identification of unknown drugs by observing colour changes when reagents are added, indicating the presence of specific functional groups or compounds.
what piece of equipment is used to confirm the drugs identity
GC-MS
how do you conduct a colour test?
Add unknown drug to spot plate/test tube, add reagent, and observe immediate colour change
what is a negative control
when the reagent is in a well on its own and does not change colour
what is a positive control
standard reference material + reagent = unknown drugs colour test
what does Marquis test for?
Opioids, Amphetamines, alkaloids, and magic mushrooms
what does Ehrlichs test for?
Lysergic acid diethylamide (LSD)
What does Duquenois Levine test for?
Tetrahydrocannabinol (THC) - main psychoactive ingredient in cannabis
what does Cobalt thiocyanate test for?
Cocaine
what does Dille-Koppanyi test for?
Barbiturates (downers)
what does Simons’ test for?
Distinguish between amphetamine and Methamphetamine
what does Libermann’s test for?
Target phenol and amine functional group found in drugs – amphetamine or paracetamol
What is the role of chromophores in colour tests?
Chromophores absorb and emit light in the visible spectrum, causing colour changes in the presence of specific molecules.
What kind of molecule produces the colour changes in colour tests?
Molecules with conjugated systems, transition metals, or carbocations are involved in producing visible colour changes in response to reagents.
what type of bond is a sigma bond?
single
what kind of bond is a pi bond?
double or triple
what does the Marquis reagent cause in relation to molecular structure?
causes a change in the structure and the binding of the molecule
what colour is produced by Marquis + Morphine/Heroin
Purple
what colour is produced between Marquis + Magic mushrooms
Yellow
what colour is produced between Marquis + Ecstasy
Orange to black
what colour is produced between Marquis + Methamphetamine
Orange
what colour is produced between Marquis + amphetamine
Orange to red to brown
What is the Ehrlichs regent composed of?
1% p-dimethylaminobenzaldehyde dissolved in conc HCL in ethylacetate
what does a positive Ehrlichs produce
a blue/purple carbocation
what is the libermann’s reagent made up of?
a solution of potassium or sodium nitrate dissolved in sulphuric acid
what does a positive Libermanns test produce in acidic conditions
a red colour quinone imine
what does a positive Libermanns test produce in basic conditions?
a blue colour quinone imine
what is Duquenois-Levine reagent made up of?
sequential addition of three solutions:
a. 2% vanillin and 1% acetaldehyde in ethanol
b. concentrated HCL
c. Chloroform
what does a positive Duquenois-Levine test produce?
a purple coloured chromaphore
what colour is produced when Fast Blue BB Salts react with THC?
red azo dye
what colour is produced when Fast Blue BB Salts react with Cannabinol?
purple azo dye
what colour is produced when Fast Blue BB Salts react with Cannabidol?
Orange azo dye
what does the Fast Blue BB Salt produce in general?
an azo dye
what is the Cobalt thiocyanate reagent made up of?
thiocyanate (2%) in concentrated HCL
what does the Cobalt Thiocyanate reagent produce in a positive test?
a blue ion pair
what is the Dille-Koppanyi reagent made up of?
1% cobalt acetate in methanol
followed by
5% isopropylamine in methanol
what colour is a positive Dille Koppanyi test?
a violet blue transition metal complex
what is Simons reagent made up of for methamphetamine?
2% nitroprusside solution containing acetaldehyde
What is the significance of microcrystalline tests in drug analysis?
They help determine the crystalline structure of drugs, which can assist in identifying specific isomers of substances.
How do you undergo a microcrystalline test?
Add unknown drug to a microscope slide
Reagents - Gold chloride, gold bromide, platinum chloride, platinum bromide
Add a cover slip
View under a transmitted light microscope
what drug has a plant matter appearance
Cannabis
what drug has a resin appearance
Cannabis or Heroin
what drug comes as Microdots, gelatine squares, and blotter papers
LSD
what drugs come in white powders
Heroine or Cocaine
what drugs come as tan powders
Heroin and Amphetamine
What are the 5 P’s?
Powders
Plant matter
Pills
Precursors – compounds used in the clandestine synthesis of drugs such as methamphetamines.
Paraphernalia – the implements and equipment used in the preparation and ingestion of drugs; e.g. a syringe
what does cocaine look like in a microcrystalline test?
sword-like
what does amphetamine look like in a microcrystalline test?
plant-like
what does methadrone look like in a microcrystalline test?
little bundles - like roses
what does GHB look like in a microcrystalline test?
rectangular crystals
what kind of microscope is used in microcrystalline tests?
transmitted light microscopes
what is the science behind colour tests?
the reagent will cause a change in the structure of the drug, allowing ground state electrons to absorb a large amount of light and become excited, and move to the excited state for a short period of time. The light they absorb will be photons of a coloured light opposite to the colour on the colour wheel that the chromophore will emit when the electrons return to ground state. For example; Marquis + Methamphetamine = the chromophore will absorb blue light and emit orange light.
what does Simons test + Methamphetamine produce
a blue coloured Simon-Awe complex
what does Simons test + Amphetamine produce
a purple complex (NOT SIMON-AWE)
what is the Simons reagent made up of for Amphetamine?
2% Nitroprusside solution in acetone
