Methods of Chemical Analysis. Selecting an Analytical Technique Organic vs. Inorganic materials ...
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Transcript of Methods of Chemical Analysis. Selecting an Analytical Technique Organic vs. Inorganic materials ...
Methods of Methods of Chemical AnalysisChemical Analysis
Selecting an Analytical Selecting an Analytical TechniqueTechnique
Organic vs. Inorganic materialsOrganic vs. Inorganic materials Organic: Organic: Inorganic:Inorganic:
Quantitative vs. Qualitative Quantitative vs. Qualitative determinationdetermination Must identify first then determine amountMust identify first then determine amount
ChromatographyChromatography
A means for separating and A means for separating and identifying organic mixtures into their identifying organic mixtures into their component parts by using their component parts by using their attraction to a attraction to a ________________________________ while being propelled through a while being propelled through a __________________________________
Types of ChromatographyTypes of Chromatography1.1. __________________________________________ : Used : Used
to identify inks and other dyes. The to identify inks and other dyes. The molecules will travel at different molecules will travel at different speeds as they are pulled along speeds as they are pulled along paper (stationary phase) by a paper (stationary phase) by a solvent (mobile phase). Thus solvent (mobile phase). Thus separating the mixture.separating the mixture.
http://chemscape.santafe.cc.fl.us/chemscape/catofp/chromato/paper/paper.htm#description
Paper ChromatographyPaper Chromatography
2. Gas Chromatography 2. Gas Chromatography (GC)(GC)
Separates mixtures on the basis of their Separates mixtures on the basis of their distribution between a stationary liquid distribution between a stationary liquid phase and a moving gas phase.phase and a moving gas phase.
Can separate highly complex mixtures Can separate highly complex mixtures within minuteswithin minutes Carrier Gas: moving phaseCarrier Gas: moving phase Packed or Capillary Column: Heated Packed or Capillary Column: Heated
thin layer of liquid contained within thin layer of liquid contained within columncolumn
Gas ChromatographyGas Chromatography
Gas Chromatography Gas Chromatography cont…cont…
Pyrolysis GCPyrolysis GC : :
Pyrolysis: Pyrolysis:
Pyrogram:Pyrogram:
3. High Performance Liquid 3. High Performance Liquid Chromatography (HPLC)Chromatography (HPLC)
Moving phase is a liquid that is pumped Moving phase is a liquid that is pumped over chemically treated solid particles over chemically treated solid particles (stationary phase). The liquid carries the (stationary phase). The liquid carries the sample over the particles and they sample over the particles and they ““stickstick”” to particles at different spotsto particles at different spots
Performed at room tempPerformed at room temp Used for Used for
HPLCHPLC
HPLCHPLC
HPLCHPLC
4. Thin Layer 4. Thin Layer Chromatography (TLC)Chromatography (TLC)
Thin Layer Plate: Thin Layer Plate:
Sample will separate out as moves up Sample will separate out as moves up gel plategel plate
TLC ChromatogramTLC Chromatogram
5. Electrophoresis5. Electrophoresis
Separation of molecules through their Separation of molecules through their migration on a gel medium migration on a gel medium
Materials are pulled through by electric Materials are pulled through by electric charge of samplecharge of sample
Used for characterization ofUsed for characterization of
ElectrophoresisElectrophoresis
ElectrophoresisElectrophoresis
ElectrophoresisElectrophoresis
SpectrophotometrySpectrophotometry
Analytical method for identifying a Analytical method for identifying a substance by substance by
Instrument used to measure and record Instrument used to measure and record absorption spectrum of a chemical absorption spectrum of a chemical substancesubstance
Relates to the Relates to the amount of substanceamount of substance Variety of types:Variety of types:
Mass SpectrometerMass SpectrometerMass SpecMass Spec: Identifies and Measures the : Identifies and Measures the
amount of substance found in a sampleamount of substance found in a sample Computer AttachedComputer Attached: records, stores and : records, stores and
compares large amounts of data with a compares large amounts of data with a mass spectra librarymass spectra library
Important for analyzing:Important for analyzing: Samples must be pureSamples must be pure
So what do you do first?So what do you do first?
Mass SpectrometerMass Spectrometer
Mass SpectrometryMass Spectrometry
Mass SpectrometryMass Spectrometry
Mass SpecMass Spec
Inorganic AnalysisInorganic Analysis Important Instrumentation for determining the Important Instrumentation for determining the
components of:components of:
Example: Kennedy Assassination Example: Kennedy Assassination The analysis of the bullet contents leads to some puzzling The analysis of the bullet contents leads to some puzzling
questionsquestions http://www.edwardjayepstein.com/archived/state.htm
Atomic Absorption SpectrophotometerAtomic Absorption Spectrophotometer::-Detects -Detects trace elementstrace elements -Also useful for establishing the source of materials in -Also useful for establishing the source of materials in evidenceevidence
Absorption & Emission SpectraAbsorption & Emission Spectra
Neutron Activation AnalysisNeutron Activation Analysis
Provides a nondestructive method of identifying Provides a nondestructive method of identifying and quantifying trace elements most sensitive and quantifying trace elements most sensitive method for quantifyingmethod for quantifying InvolvesInvolves
Can simultaneously analyze 20-30 elementsCan simultaneously analyze 20-30 elements Extremely expensive – sophisticated method needs Extremely expensive – sophisticated method needs
a lot of training (can you guess why?)a lot of training (can you guess why?) Used for analyzingUsed for analyzing
Neutron ActivationNeutron Activation
X- Ray DiffractionX- Ray Diffraction
Aiming a beam of X-rays at crystals Aiming a beam of X-rays at crystals reveals a diffraction pattern. reveals a diffraction pattern.
Every compound produces its own Every compound produces its own unique patternunique pattern
Used forUsed for
Comparison of X- Ray Comparison of X- Ray Diffraction PatternsDiffraction Patterns
Ugh…. Ugh…. Glad that one is over. Glad that one is over. Do you think they are?Do you think they are?