Download Chapter 5

Chapter 5: Organic Analysis
Figure 2.19 A molecular mimic
Objective:
You will be able to explain the basic
properties and functions of carbohydrates
Organic vs. Inorganic
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Organic contains Carbon AND
Hydrogen
4 Types of organic compounds
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids
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Readily available source of energy
Serve as raw material for synthesis of other
molecules
Used as a structural component
One type is called a monosaccharide
What do all monosaccharides have in common?
Paired Activity

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Create a unique monosaccharide based on
the criteria discussed.
After you have built your molecule, write
down what YOU think makes it unique.
Figure 5.4 Linear and ring forms of glucose
Figure 5.7b,c Starch and cellulose structures
Cellulose–laced missiles
AIM 9-L/M "SIDEWINDER"
CH2O
H
O OH
H
H
OH H
OH
H
H
NH
C
O
CH3
(a) The structure of the
chitin monomer.
gure 5.10 A–C
What popular drug is created from carbohydrates?
Objective: You will be able to state the properties
of lipids and proteins
Lipids
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All are hydrophobic
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Three types:
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Triacylglycerols (fats)
Phospholipids
Steroids
FATS
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Triacylglycerol or fat is made up of 3
fatty acids and one glycerol
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Are significant to forensics because
many substances are stored in fats
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PCB’s
Marijuana, Cocaine, etc…
Because they are stored, there affect may
be long lasting
3D lipids
Proteins
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Made up of a specific sequence of amino
acids
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Each protein has its own specific number of
amino acids and in its own unique order
This sequence will lead to a specific shape
that will give the protein its function
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Ex. Enzymes, hormones
Proteins
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Proteins have many functions in the body
A key function is that they act as chemical
messengers

Many of the illegal drugs cause their affect
because they act as messengers
Overview of cell signaling
EXTRACELLULAR
FLUID
1
Reception
CYTOPLASM
Plasma membrane
2
Transduction
3
Response
Receptor
Activation
of cellular
response
Relay molecules in a signal transduction pathway
Signal
molecule
Figure 11.5
Drugs that act as messengers
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Opiates
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Morphine
Heroin
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These chemicals help reduce pain
Three neurons engage in opiate action. When opiates bind to opiate receptors, a signal goes to the
dopamine terminal (shown here as part of another neuron) to release dopamine. Dopamine binds to
dopamine receptors, stimulating the post-synaptic cell and a positive emotional feeling
Nucleic Acids
DNA
 Stores genetic information
 Double stranded
 Is transcribed to synthesize proteins
__________________________________________
RNA
 Translates DNA and carries out protein synthesis
 Single stranded
Paired Activity

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Use DNA kits to build DNA
Create a key for the parts
Hints
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Yellow is for covalent bonds between the
sugar and the phosphate
Look at number of bonds for each part
You have enough to create 6 nucleotides on
each side
Objective:
You will be able to describe the
theory of chromatography.
Analyzing Organic Compounds
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Quality versus quantity
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Quality identifies exactly what it is
Quantity may be important because larger
amounts of illegal substances may carry
longer jail time
Many times substances are in fact mixtures
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Drug dealers may “cut” the drugs
This requires a different technique to identify
the substance
Chromatography
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This technique has the ability to purify
substances
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It rips each component from mixture and
separates it single components
Theory of chromatography
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Chemical substances partially escape into
surroundings when:
Dissolved in a liquid
 Absorbed into a solid
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Dissolved in liquid
Dissolved on a solid
Gas chromatography
TLC
Thin Layer Chromatography (TLC)
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Separation of mixture is done by using a
stationary solid phase (paper) and moving
liquid phase
Still based on solubility of each substance
in the liquid
Substances that are highly soluble move
faster
Analyzing the TLC sample
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A measurement of how far each component
of a substance would then be taken
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This will determine the RF value of a
substance
A substances RF value can be used to HELP
determine what it is
Not unique and other substances may have
same RF value
A direct comparison can also be made by
running a known sample versus and
unknown
Activity:
We need to find out who wrote that note!!!
 Work with your group to develop a method to
determine whose pen was used.
 You need to:
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Give the names of the suspects
State which method you are going to use
Describe the “science” behind the method
Provide an outline of steps you are going to use
Gas Chromatography
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Can separate substances because of differences in
solubility in a liquid
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Force air to continuously move in one direction
Gas phase is moving phase, liquid phase is stationary
phase
The chemical race
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High solubility means it wants to stay in liquid
This makes the highly soluble substance move slower
Objective:You will be able to explain how GC
can be used for the quantitative and qualitative
analysis of compounds.
Do Now:
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Read “Gas Chromatography” on p. 123 and
only first paragraph on 124
Differentiate between the two types of columns
used in GC
Activity
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Work in pairs to create a parts list for the
gas chromatography machine
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Make sure you draw each part and give its
function
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Use the diagram on p. 136 to help you
Gas Chromatography
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Uses a stationary liquid phase and a moving gas
phase
Can separate substances because of differences
in solubility in a liquid
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High solubility means it wants to stay in liquid
The chemical race
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Force air to continuously move in one direction
Gas phase is moving phase, liquid phase is
stationary phase
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Need large enough area so that the molecules can be fully
separated
The GC Machine
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Sample is placed into the injector and
travels through the column
Carrier gas is typically nitrogen or helium
Column is heated to keep substance being
tested in a gaseous state
As each substance in the sample emerges
from the column, it enters a detector
Here it is ionized by a flame that creates an
electric signal
 This signal creates a chart called a chromatogram

Components of a Gas Chromatograph
Creates a
chromatogram
Sample
injected here
Inert gas
This is heated to keep
sample in gas state
Chromatograms
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Chromatograms are plotted based on
retention time
Usually has a series of peaks which
represents each substance from a mixture
Qualitative analysis done by comparing
retention time with known samples
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Not 100% reliable because two substances
may have same retention time
Quantitative analysis is done by viewing
how high the peak is
B
A
Each peak represents a
different substance
from the mixture
Which substance had
the highest solubility?
D
C
E
Mixture of material in marijuana
chromatograms may
also be able to identify
substances by
comparing to known
standards.
Material must be a gas to enter GC
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Some material like paint, fibers and plastics
cannot be readily dissolved into a liquid to
go into the GC machine
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A technique called pyrolysis heats these
materials so they decompose into gaseous
materials
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These materials are then injected into the GC
machine
Objective: You will be able to explain how the
mass spectrometer can be used to specifically
identify a substance.
Do Now:
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Read the chapter summary on p. 142-143
Give three things that you learned the best
in this chapter
Mass Spectrometer
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As the gas leaves the GC, it enters the MS
Within the MS, a beam of electrons is shot
at the substance breaking it down into
fragments
These fragments pass through an electric
field which separates them by their masses
The fragment masses are then recorded on
a graph
Each substance breaks down into its own
characteristic pattern
MASS
MS of Caffeine
Objective: You will be able to discuss the
various properties of light
Do Now:
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Read “Electrophoresis” on p. 131-132
How are the processes of electrophoresis
and TLC similar? Different?
What is electrophoresis used for?
Pair Work
Read page 136-137 (The Spectrophotometer)
Explain how a spectrophotometer works by
giving the function of the:
Radiation source
Monochromator
Sample cell
Detector and Recorder
Explain how samples are prepared
Objective: You will be able to explain how the
ultraviolet, visible and infrared spectrophotometer
can be used in qualitative analysis.
Do Now:
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Read “Absorption of electromagnetic
radiation” on p. 135-136
How does spectrophotometry work?
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Relate energy requirement to absorption
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