Lecture 1 - Basic chemical analysis Flashcards
What does a combination of colour tests provide?
Presumptive identification of an unknown drug
How can you provide conclusive identification of an unknown drug?
GC-MS
What does the Marquis test detect?
Opioids, Amphetamine family, alkaloids and magic mushrooms
What does the Ehrlic’s test detect?
LSD (Lysergic acid dimethylamide)
What does the Duquenois Levine test detect?
THC (Tetrahydrocannabinol)
What does the cobalt thiocyanate test detect?
Cocaine
What does the Dilli-Kopany test detect?
Barbiturates
What does the Simon test detect?
Distinguishes between amphetamine and methamphetamine
What does the Libermann’s test detect?
Targets phenol and amine functional groups
What might an unknown drug be if it has a plant matter appearance?
Cannabis
What might an unknown drug be if it has a resin appearance?
Cannabis or heroin
What might an unknown drug be if it has a Blotting paper or microdot appearance?
LSD
What might an unknown drug be if it has a White powder appearance?
Heroin or Cocaine
What might an unknown drug be if it has a Tan powder appearance?
Heroin or amphetamine
How are colour tests performed?
- A small amnt of the unknown substance placed in a spot plate
- A small amnt of reagant is added to the substance
- The immediate colour change is observed and noted down
How is negative control used?
- A small amnt of the test reagant is added to a blank well on the spot plate
- If no colour change is observed, the substance has negative control
- If a colour change is observed, contamination has occured
How is positive control used?
- A standard reference material is obtained and added to a spot plate
- A small amnt of reagant is added
- The immediate colour change is noted and compared with that of the unknown substance
What is a chromophore?
A molecule that absorbs and emits wavelengths of light in the visible region
What are the 3 types of chromophore produced from colour tests?
- Azo dyes
- Transition metal complex
- Carbocation
What is the molecular formula for an azo dye?
R-N=N-R
What does a transition metal complex consist of?
A transition metal (e.g. cobalt) surrounded by other molecules
What can affect the colour of a transitional metal complex?
The addition of anionic, cationic and neutral ligands (ammonia groups)
What are carbocations?
Positively charged carbons
What is a primary carbocation?
A positively charged carbon surrounded by either 3 hydrogens or 2 hydrogens and an organic group
What is a secondary carbocation?
A positively charged carbon surrounded by 1 hydrogen and 2 organic groups
What is a tertiary carbocation?
A positively charged carbon surrounded by 3 organic groups
Which is the most stable carbocation?
Tertiary carbocation
Which is the least stable carbocation?
Primary carbocation
What are sigma bonding orbitals associated with?
Sigma electrons (Single bonds)
What are Pie bonding orbitals associated with?
Pie electrons (Double or triple bonds)
What are n bonding orbitals associated with?
Electrons that are not involved in bonding
When electrons are bombarded with light, what happens?
They are excited from the ground state to the excited state
How long do excited electrons stay in the excited state?
A short period of time, before they excite back down
What happens as the electrons excite back down?
They emit photons of light