4103FSBMOL - Lecture 1 - Basic Forensic Analysis. Flashcards
Colour Tests, Microcrystalline Tests and Molecular Orbitals.
1
Q
What are the 2 types of Basic Forensic Analysis Tests?
A
Colour Tests and Microcrystalline Tests.
2
Q
What are Colour Tests also known as and what are they used for?
A
Presumptive or Spot Tests. They are used as a Screening Tool in Routine Drug Analysis.
3
Q
What Type of Identification do Colour Tests provide?
A
TENTATIVE (provisional) identification.
4
Q
What needs to follow a colour test to prove that it is a certain drug for example?
Give an example.
A
A Confirmatory Test such as GC-MS.
5
Q
What is a Microcrystalline test?
A
They are chemical tests resulting in the formation of unique microcrystals for a given substance when combined with a specific reagent.
6
Q
Name all the Different Types of Colour Test.
A
- Marquis Reagent Test.
- Ehrlich’s Test.
- Duquenois-Levine Test.
- Cobalt Thiocynate Test.
- Dille-Koppanyi Test.
- Simon Test.
- Libermann’s Test.
- Ferric Chloride Test.
- Iodine Test.
- Amalic Test.
- Mandelin’s Test.
- Mecke’s Test.
- Froehde Test.
- Fast Blue BB Salt Test.
7
Q
What is the MAIN Colour Test you always have to start with?
A
The Marquis Reagent Test.
8
Q
What is the Marquis Reagent Test used to detect for?
A
- Opoids - Heroin, Morphine, Codeine, Opium.
- Amphetamine Family - Amphetamine, Methamphetamine and Ecstasy.
- Alkaloids - e.g. Cocaine.
- Magic Mushrooms.
9
Q
What is the Ehrlich’s Test used to detect?
A
Lysergic Acid Diethylamide - LSD.
10
Q
Whats the Duquenois-Levine Test used to detect?
A
Tetrahydrocannabinol - THC.
11
Q
What is the Cobalt Thiocynate Test used to detect?
A
Cocaine.
12
Q
What is the Dille-Koppanyi Test used to detect?
A
Barbiturates.
13
Q
What is the Simon Test used to detect/ distinguish between?
A
It is used to distinguish between Amphetamine and Methamphetamine.
14
Q
What is the Libermann’s Test used to detect?
A
The Phenol and Amine functional groups in drugs.
15
Q
What is the Ferric Chloride Test used to detect?
A
- Salicylates.
- Alkaloids.
- Phenols.
16
Q
What is the Iodine Test used to detect?
A
Starch.
17
Q
What is the Amalic Test used to detect?
A
Xanthines (e.g. Caffeine).
18
Q
What is the Mandelin’s Test used to detect?
A
- Steroids.
- Alkaloids.
- Aspirin.
19
Q
What is the Mecke’s Test used to detect?
A
Alkaloids (organic compound containing at least 1 nitrogen atom).
20
Q
What is the Froehde Test used to detect?
A
- Codeine.
- Opium.
- LSD.
21
Q
What is the Fast Blue BB Salt Test used to detect/ differentiate between?
A
It is used to differentiate between metaboiltes (THC), cannabinol and cannabidol.
22
Q
What is the Marquis Reagent made up of?
A
2% Formaldehyde in Concentrated Sulphuric Acid.
23
Q
What colour does Morphine go when the Marquis Reagent is added?
A
Purple.
24
Q
What colour does Heroin go when the Marquis Reagent is added?
A
Purple.
25
What **colour** does *Magic Mushrooms* go when the *Marquis Reagent* is added?
Yellow.
26
What **colour** does *Ecstasy* go when the *Marquis Reagent* is added?
Orange to Black.
27
What **colour** does *Methamphetamine* go when the *Marquis Reagent* is added?
Orange.
28
What **colour** does *Amphetamine* go when the *Marquis Reagent* is added?
Orange-Red-Brown.
29
Which 2 drugs go **purple** when the *Marquis Reagent* is added?
Morphine and Heroine.
30
What drug goes **Yellow** when the *Marquis Reagent* is added?
Magic Mushrooms.
31
What drug goes **Orange to Black** when the *Marquis Reagent* is added?
Ecstasy.
32
What drug goes **Orange** when the *Marquis Reagent* is added?
Methamphetamine.
33
What drug goes **Orange-Red-Brown** when the *Marquis Reagent* is added?
Amphetamine.
34
How does the **Mechanism** work in the *Marquis Reagent Test?*
The Formaldehyde (CH2O) structure reacts with the Benzene Ring part of the structure to form an *unstable Primary Carbocation.* Another of the same molecule is added and this results in a *secondary carbocation which is a **stable** dimer.*
35
What **Reagents** are used in the *Ehrlich's Test?*
*1%* para-dimethylaminobenzaldehyde (p-DMBA) dissolved in *concentrated* HCl in ethylacetate.
36
What type of reaction is the Ehrlich's Test?
A **Condensation** Reaction - water is lost.
37
What **colour change** happens when *LSD* reacts with the *Ehrlich's Reagent?*
A **Blue/ Purple/ Pink** Tertiary Carbocation is formed.
38
How does the **Mechanism** work in the *Ehrlich's Test?*
The LSD molecule reacts with p-DMBA to form a carbinole which undergoes a condensation reaction to form an *unstable secondary carbocation.* A proton is added and further LSD molecules to form a ***Stable** Tertiary Carbocation.*
39
What **Reagents** are used in the *Libermann's Test?*
A solution of potassium/ sodium nitrate dissolved in **concentrated** sulphuric acid.
40
What **colour change** happens when a molecule containing *a phenol/ amine group* reacts with the *Libermann's Reagent?*
* **Red** coloured Quinone imine (***Acidic*** Conditions).
* **Blue** coloured Quinone imine (***Basic*** Conditions).
## Footnote
*Quinone imine - Electrophile (accept electrons).*
41
How does the **Mechanism** work in the *Libermann's Test?*
A Phenol group reacts with the potassium/ sodium nitrate and sulphuric acid to make a Nitroso Phenol. More Phenol molecules are reacted with Sulphuric Acid to form a coupled intermediate. This loses water to form the product based on acidic or basic conditions.
42
What **Reagents** are used in the *Duquenois-Levine Test?*
_The Sequential addition of:_
**1)** *2%* vanillin and *1%* acetaldehyde in ethanol.
**2)** *Concentrated* HCl.
**3)** Chloroform (non-polar).
43
What **colour change** happens when *THC* reacts with the *Duquenois-Levine Reagents?*
Goes from *Colourless/Yellow* to *Purple/blue* colour from the addtion of No.1 to No.2. Finally, a **purple** coloured chromophore is formed.
## Footnote
Chromophore - a molecule that absorbs light of a specific wavelength and reflects color, making it a colored molecule.
44
How does the **Mechanism** work in the *Duquenois-Levine Test?*
THC undergoes an adol
condensation reaction followed by an electrophilic aromatic substitution resulting in the proposed chromophore structure.
45
What **Reagents** are used in the *Cobalt Thiocyanate Test?*
*2%* Cobalt Thiocyanate Solution dissolved in *conctrated* HCl.
46
What **colour change** happens when *Cocaine* reacts with the *Cobalt Thiocyanate Reagent?*
A **Blue** Coloured *Ion Pair* is formed.
47
How does the **Mechanism** work in the *Cobalt Thiocyanate Test?*
When Cocaine comes into contact with HCl it immediately ionises to form the cocaine cation which reacts with the cobalt thiocyanate to form the blue coloured ion pair.
48
What **Reagents** are used in the *Dilli-Koppanyi Test?*
_Sequential addition of:_
**1)** *1%* cobalt acetate in methanol.
**2)** *5%* isopropylamine in methanol.
49
What **colour change** happens when *Barbiturates* reacts with the *Dilli-Koppanyi Reagent?*
A **violet-blue** coloured transition metal complex is formed.
50
How does the **Mechanism** work in the *Dilli-Koppanyi Test?*
When the reagents are added, each of the reactants bond to the same Cobalt atom to *form a dative transition metal complex* formed of barbiturate molecules opposite each other and isopropalamine molecules opposite each other.
51
What **Reagents** are used in the *Simon Test?*
* *2%* Nitroprusside solution containing **Acetaldehyde** - detection of Methamphetamine.
* *2%* Nitroprusside solution in **Acetone** - detection of Amphetamine.
52
What **colour change** happens when *Methamphetamine* reacts with the *Simon Test Reagent?*
A **Blue** Simon-Awe Complex is formed.
53
What **colour change** happens when *Amphetamine* reacts with the *Simon Test Reagent?*
A **Purple** Complex is formed.
54
How does the **Mechanism** work in the *Simon Test?*
A (Meth)Amphetamine molecule reacts with the (acetaldehyde/acetone) and loses water to form an *Enamine.* This then reacts with the Nitroprusside to form an *Ammonium Salt* and then water is lost to form the Simon-Awe Complex.
## Footnote
* Acetaldehyde reacts with *Meth*amphetamine.
* Acetone reacts with Amphetamine.
55
Which is the **only** Colour Test to produce Azo Dyes?
The Fast Blue BB Salt Test.
56
What **Reagents** are used in the *Fast Blue BB Salt Test?*
Fast Blue BB Salt Solution.
57
What **colour change** happens when *THC* reacts with the *Fast Blue BB Salt Reagent?*
A **Red** *Azo Dye* is produced.
58
What **colour change** happens when *Canna**bin**ol* reacts with the *Fast Blue BB Salt Reagent?*
A **Purple** *Azo Dye* is produced.
59
What **colour change** happens when *Canna**bid**ol* reacts with the *Fast Blue BB Salt Reagent?*
An **Orange** *Azo Dye* is produced.
60
How does the **Mechanism** work in the *Fast Blue BB Salt Test?*
Its due to the coupling reaction between the diazonium group of the fast blue bb salts and the activating group (-OH) of phenolic compounds such as THC, CNB and CND.
## Footnote
* CNB - Cannabinol.
* CND - Cannabidol.
61
What *Drug* is known to always come in a **'Plant Matter'** form?
Cannabis.
62
What *Drugs* are known to come in a **'Resin'** form?
Cannabis or Heroin.
63
What *Drug* is known to come as **'Microdots, gelatin squares or blotter papers'?**
LSD.
64
What *Drugs* are known to come in a **'White Powder'** form?
Heroin or Cocaine.
65
What *Drugs* are known to come in a **'Tan Powder'** form?
Heroin or Amphetamine.
66
What are Tan Powders also known as?
**Street Drugs** (cut with adulterants such as Caffeine or Bleach).
67
How do you perform a Routine *Colour Test?*
1. A small amount of the suspected drug substance is placed into the tile of a spotting plate.
2. A few drops of reagent are added and the **IMMEDIATE** colour change is noted down.
3. A *Negative* Control Test is performed.
4. A *Positive* Control Test is performed to Tentatively identify the drug.
68
How do you complete a **Negative** Control Test?
A drop of reagent is added into a spotting well with no substance, and it is a *Negative result* if the *colour doesn't change.* If it changes colour, then there is *possibility of contamination*, therefore analysis has to be done all over again.
69
How do you complete a **Positive** Control Test?
Standard reference material (e.g. the drug comparing to from 'the bank') is added to a well and the same reagent(s) are added. The immediate colour change is recorded and compared to the unknown.
## Footnote
Same Colour Change = **TENTATIVE** Identification.
70
How do you perform a Routine *Microcrystalline Test?*
1. Place the unknown drug onto a microscope slide.
2. Add a few drops of reagent *(gold chloride/ bromide or platinum chloride/ bromide).*
3. Place a Cover Slip on top and analyse under a **transmitted light microscope.**
71
What *structure* of Microcrystal can **Cocaine Crystals** be described as having?
**Sword-like** Crystals.
72
What *structure* of Microcrystal can **Amphetamine Crystals** be described as having?
**Plant-like** Crystals.
73
What *structure* of Microcrystal can **Mephedrone Crystals** be described as having?
**Poses/ Flower-like** Crystals.
74
What *structure/ shape* of Microcrystal can **GHB Crystals** be described as having?
**Rectangular** Crystals.
75
Which one of the 4 microcrystalline drugs is **not** used in *routine* drug analysis testing?
**GHB** (Gamma-hydroxybutyrate/ 4-hydroxybutanoic acid).
76
What are the 3 possible types of coloured compound/ chromaphore which can be produced by colour tests?
* Azo Dyes.
* Transition Metal Complexes.
* Carbocations.
77
What type of chemical *structure* do **Azo Dyes **have?
R-N=N-R.
78
What **charge** do *Carbocations* have?
**Positive (+).** This makes them very very reactive.
79
In Transition Metal Complexes, what are the names of the parts surrounding the central transition metal atom?
Ligands.
80
What things affect the colour of a transition metal complex?
* Type of Transition Metal.
* Oxidation State(s).
* Type of Ligands.
81
What is the **order of stability** for *Carbocations?*
**_MOST STABLE_**
1. *Tertiary (3°)* Carbocations (3 organic Groups).
2. *Secondary (2°)* Carbocations (2 organic groups).
3. *Primary (1°)* Carbocations (1 organic group).
**_LEAST STABLE_**
82
What is a Chromaphore?
Substances which absorb and emit light in the *visible* region of the electromagnetic spectrum.
83
In terms of Molecular Orbitals, what does GS and ES mean?
## Footnote
What are they joined in the middle by?
* GS = **Ground** State.
* ES = **Excited** State.
## Footnote
They are joined by an 'energy gap' in the middle.
84
What are the differences between the Ground State and the Excited State?
* The Ground State is the **lowest** energy (ΔE) and only contains bonding orbitals.
* The Excited State is the **highest** energy (ΔE) and only contains ***anti-***bonding orbitals.
85
What **type of bonding orbitals** are associated with *single bonds?*
**Sigma (σ)** orbitals.
86
What **type of bonding orbitals** are associated with *double and triple bonds?*
**Pi (π)** orbitals.
87
What **type of bonding orbitals** are ***not*** associated with bonding?
**n** orbitals.
88
What **type of bonding orbitals** are found in the *Ground State?*
Sigma (σ) bonding, Pi (π) bonding and n bonding orbitals.
89
What **type of bonding orbitals** are found in the *Excited State?*
Sigma (σ)* **anti**-bonding and Pi (π)* **anti**-bonding orbitals.
90
How do electrons get transferred from the Ground State to the Excited State?
When electrons are **bombarded with light.**
91
How long do electrons stay in the excited state?
A **SHORT** length of time.
92
Electrons ____________ photons to get excited to the Excited State and ____________ photons to relax to the ground state.
## Footnote
Photons - light molecules.
1. Absorb.
2. Emit.
93
What can you use to determine what colour is emitted when a certain colour of light is absorbed?
The Artists Colour Wheel.
94
What **colour light is Emitted** when *Orange light is Absorbed?*
**Blue** Light.
95
What **colour light is Emitted** when *Red light is Absorbed?*
**Green** light.
96
What **colour light is Absorbed** when *Violet light is Emitted?*
**Yellow** light.
97
What does the Marquis reagent do to a molecule?
It changes the Structure and Bonding.
98
The energy required for an electron to be excited is __________ to that energy provided by a photon of __________ light.
## Footnote
1. Equal/ Different.
2. Colour.
1. Equal.
2. Blue.
99
# **_Practice Question:_**
"When marquis reagent reacts with methamphetamine it produces an *orange* coloured carbocation. What chemistry is involved to produce this reaction?"
The Marquis reagent causes a **change in the structure** of the methamphetamine. The electrons **absorb photons of blue light** to allow them to be excited from the ground state to the excited state and **emit photons of orange light** (orange carbocation).
100
# **_Practice Question:_**
"An unknown powder has been found in the raid of a clandestine laboratory. The police *believe that the powder is cocaine.* What *combination of tests* could be undertaken to identify the composition of the white powder."
Firstly **add the Marquis reagent** to a sample of the small powder in a spotting well. The *colour shouldn't change.* Then do the **Cobalt Thiocyanate test** to another small sample of the powder. This should **produce a *blue ion pair*** as this is the main test for cocaine. You could also do the Mandelin's test and the Ferric Chloride Test. These are all *tentative tests* and to **confirm the presence of cocaine, you need to analyse with a GC-MS.**
