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Chapter 5: Chapter 5: Organic AnalysisOrganic Analysis
A common dose estimate for acute toxicity is A common dose estimate for acute toxicity is the LD50 (Lethal Dose 50%). This is a the LD50 (Lethal Dose 50%). This is a statistically derived dose at which 50% of the statistically derived dose at which 50% of the individuals will be expected to die. individuals will be expected to die.
Acute toxicity (LD50 mg/kg) Acute toxicity (LD50 mg/kg) of acetaminophenof acetaminophen
SpeciesOral
Rat 2680-3100
Mouse 338
Hamster 630-770
Rabbit 2640-2800
Dog 1180-1450
mg/Kg
Acetaminophen metabolites found in urineAcetaminophen metabolites found in urine
Figure 2.19 A molecular mimicFigure 2.19 A molecular mimic
Objective:Objective: You will be able to You will be able to explain the basic properties and explain the basic properties and functions of carbohydratesfunctions of carbohydrates
Organic vs. InorganicOrganic vs. Inorganic•CarbohydratCarbohydrateses•LipidsLipids•ProteinsProteins•Nucleic AcidsNucleic Acids
•WaterWater•Carbon Carbon dioxidedioxide•OxygenOxygen•MethaneMethane
CarbohydratesCarbohydrates
Readily available source Readily available source of energyof energy
Serve as raw material for Serve as raw material for synthesis of other synthesis of other moleculesmolecules
Used as a structural Used as a structural componentcomponent
Three major types is Three major types is called: called: monosaccharide, monosaccharide, disaccharidesdisaccharides
polysaccharides polysaccharides
What do all Monosaccharide's have in common?What do all Monosaccharide's have in common?
Paired ActivityPaired Activity• Create a unique Create a unique
monosaccharide based on monosaccharide based on the criteria discussed.the criteria discussed.
• After you have built your After you have built your molecule, write down molecule, write down what YOU think makes it what YOU think makes it unique.unique.
Figure 5.4 Linear and ring forms of glucoseFigure 5.4 Linear and ring forms of glucose
Figure 5.7b,c Starch and cellulose structures Figure 5.7b,c Starch and cellulose structures
(a)
O
CH2OH
OHH
H OH
H
NH
C
CH3
O
H
H
OH
Figure 5.10 A–C
The structure of the chitin monomer.The structure of the chitin monomer.
What popular drug is created from carbohydrates?
Objective:Objective: You will be able to You will be able to state the properties of lipids and state the properties of lipids and proteinsproteins
LipidsLipids
Fats, oils and waxesFats, oils and waxes All are hydrophobicAll are hydrophobic
Three types:Three types: TriacylglycerolsTriacylglycerols PhospholipidsPhospholipids SteroidsSteroids
FATSFATS Triacylglycerol or fat is made up of 3 Triacylglycerol or fat is made up of 3
fatty acids and one glycerol fatty acids and one glycerol
Are significant to forensics because Are significant to forensics because many substances are stored in fatsmany substances are stored in fats PCB’sPCB’s Marijuana, Cocaine, etc…Marijuana, Cocaine, etc… Because they are stored, there affect may Because they are stored, there affect may
be long lastingbe long lasting
ProteinsProteins• Made up of a specific
sequence of amino acids– 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– Ex. Enzymes, hormones
ProteinsProteins• 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
EXTRACELLULARFLUID
Receptor
Signal molecule
Relay molecules in a signal transduction pathway
Plasma membraneCYTOPLASM
Activationof cellularresponse
Figure 11.5
Overview of cell signalingOverview of cell signaling
Reception1 Transduction2 Response3
Drugs that act as messengersDrugs that act as messengers• Opiates
– Morphine– Heroin
• These chemicals help reduce pain
Opiate ReceptorsOpiate Receptors
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 AcidsNucleic AcidsDNADNA
Stores genetic informationStores genetic information Double strandedDouble stranded Is transcribed to synthesize proteinsIs transcribed to synthesize proteins
____________________________________________________________________________________
RNARNA Translates DNA and carries out protein synthesisTranslates DNA and carries out protein synthesis Single strandedSingle stranded
Objective:Objective: You will be able to describe the theory of You will be able to describe the theory of chromatography.chromatography.
Analyzing Organic Analyzing Organic CompoundsCompounds
• Quality versus quantity– 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– Drug dealers may “cut” the drugs– This requires a different technique to
identify the substance
ChromatographyChromatography
• This technique has the ability to purify substances– It rips each component from
mixture and separates it single components
• Theory of chromatography– Chemical substances
partially escape into surroundings when:
• Dissolved in a liquid• Absorbed into a solid
Dissolved in liquid Dissolved on a solidDissolved on a solid
Gas chromatography TLC
Thin Layer Chromatography Thin Layer Chromatography (TLC)(TLC)
• 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 sampleAnalyzing the TLC sample• A measurement of how far
each component of a substance would then be taken– 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:Activity:We need to find out who We need to find out who
wrote that note!!!wrote that note!!!• Work with your group to Work with your group to
develop a method to develop a method to determine whose pen was determine whose pen was used.used.
• You need to: You need to: – Give the names of the Give the names of the
suspectssuspects– State which method you are State which method you are
going to usegoing to use– Describe the “science” Describe the “science”
behind the methodbehind the method– Provide an outline of steps Provide an outline of steps
you are going to useyou are going to use
Gas ChromatographyGas Chromatography• Can separate substances because of
differences in solubility in a liquid– Force air to continuously move in one direction– Gas phase is moving phase, liquid phase is
stationary phase
• The chemical race– High solubility means it wants to stay in liquid– This makes the highly soluble substance move
slower
Objective:Objective:You will be able to explain how GC You will be able to explain how GC can be used for the quantitative and qualitative can be used for the quantitative and qualitative analysis of compounds.analysis of compounds.
Do Now:Do Now:• Read “Gas Chromatography” on p. 123 and Read “Gas Chromatography” on p. 123 and
only first paragraph on 124only first paragraph on 124• Differentiate between the two types of Differentiate between the two types of
columns used in GCcolumns used in GC
ActivityActivity
• Work in pairs to create a parts list Work in pairs to create a parts list for the gas chromatography for the gas chromatography machinemachine
• Make sure you draw each part and Make sure you draw each part and give its functiongive its function
• Use the diagram on p. 136 to help Use the diagram on p. 136 to help youyou
Gas ChromatographyGas Chromatography• Uses a stationary liquid phase and a
moving gas phase • Can separate substances because of
differences in solubility in a liquid– High solubility means it wants to stay in
liquid
• The chemical race– Force air to continuously move in one
direction– Gas phase is moving phase, liquid phase is
stationary phase• Need large enough area so that the molecules can
be fully separated
The GC MachineThe GC Machine• 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
Inert gas
Sample injected here
This is heated to keep sample in gas state
Creates a chromatogram
ChromatogramsChromatograms• 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– Not 100% reliable because two
substances may have same retention time
• Quantitative analysis is done by viewing how high the peak is
Each peak represents a different substance from the mixture
Which substance had the highest solubility?
A
B
C
D
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 Material must be a gas to enter GCenter GC
• Some material like paint, fibers and plastics cannot be readily dissolved into a liquid to go into the GC machine
• A technique called pyrolysis heats these materials so they decompose into gaseous materials– These materials are then injected into
the GC machine
Objective:Objective: You will be able to explain how the mass You will be able to explain how the mass spectrometer can be used to specifically identify a spectrometer can be used to specifically identify a substance.substance.
Do Now:Do Now:• Read the chapter Read the chapter
summary on p. 142-143summary on p. 142-143• Give three things that you Give three things that you
learned the best in this learned the best in this chapterchapter
Mass SpectrometerMass Spectrometer• As the gas leaves the GC, it enters As the gas leaves the GC, it enters
the MSthe MS• Within the MS, a beam of Within the MS, a beam of
electrons is shot at the substance electrons is shot at the substance breaking it down into fragmentsbreaking it down into fragments
• These fragments pass through an These fragments pass through an electric field which separates electric field which separates them by their massesthem by their masses
• The fragment masses are then The fragment masses are then recorded on a graphrecorded on a graph
• Each substance breaks down into Each substance breaks down into its own characteristic patternits own characteristic pattern
MASS
MS of CaffeineMS of Caffeine
Objective:Objective: You will be able to discuss the various You will be able to discuss the various properties of lightproperties of light
Do Now:Do Now:• Read “Electrophoresis” on Read “Electrophoresis” on
p. 131-132p. 131-132• How are the processes of How are the processes of
electrophoresis and TLC electrophoresis and TLC similar? Different?similar? Different?
• What is electrophoresis What is electrophoresis used for?used for?
Pair WorkPair WorkRead page 136-137 (The Read page 136-137 (The
Spectrophotometer)Spectrophotometer)
Explain how a spectrophotometer Explain how a spectrophotometer works byworks by
giving the function of the:giving the function of the:
Radiation sourceRadiation source
MonochromatorMonochromator
Sample cellSample cell
Detector and Detector and RecorderRecorder
Explain how samples are preparedExplain how samples are prepared
Objective:Objective: You will be able to explain how the You will be able to explain how the ultraviolet, visible and infrared spectrophotometer can ultraviolet, visible and infrared spectrophotometer can be used in qualitative analysis.be used in qualitative analysis.
Do Now:Do Now:• Read “Absorption of Read “Absorption of
electromagnetic radiation” on electromagnetic radiation” on p. 135-136p. 135-136
• How does spectrophotometry How does spectrophotometry work?work?
• Relate energy requirement to Relate energy requirement to absorptionabsorption