chromotography_notes_ghgfffgsiddy2017.ppt
- 1. Applications in Forensic Science T. Trimpe 2006 http://sciencespot.net/
- 2. What is Chromatography? Chromatography is a technique for separating mixtures into their components in order to analyze, identify, purify, and/or quantify the mixture or components. Separate • Analyze • Identify • Purify • Quantify Components Mixture Simplified Definition: Chromatography separates the components of a mixture by their distinctive affinity to the mobile phase and the stationary phase.
- 3. Terminology • Mixture – two or more substances that are physically combined • Affinity – natural attraction or force between things • Mobile Medium – gas or liquid that carries the components (mobile phase) • Stationary Medium – the part of the apparatus that does not move with the sample (stationary phase)
- 4. Uses for Chromatography Chromatography is used by scientists to: • Analyze – examine a mixture, its components, and their relations to one another • Identify – determine the identity of a mixture or components based on known components • Purify – separate components in order to isolate one of interest for further study • Quantify – determine the amount of each of the components present in the sample
- 5. Who Else Uses Chromatography? Real-life examples of uses for chromatography: • Pharmaceutical Company – determine amount of each chemical found in new product • Hospital – detect drug or alcohol levels in a patient’s blood stream • Law Enforcement – to compare a sample found at a crime scene to samples from suspects • Environmental Agency – determine the level of pollutants in the water supply • Manufacturing Plant – to purify a chemical needed to make a product
- 6. • Liquid Chromatography – separates liquid samples with a liquid solvent (mobile phase) and a column composed of solid beads (stationary phase) • Gas Chromatography – separates vaporized samples with a carrier gas (mobile phase) and a column composed of a liquid or of solid beads (stationary phase) • Paper Chromatography – separates dried liquid samples with a liquid solvent (mobile phase) and a paper strip (stationary phase) • Thin-Layer Chromatography – separates dried liquid samples with a liquid solvent (mobile phase) and a glass plate covered with a thin layer of alumina or silica gel (stationary phase) Types of Chromatography Types of Chromatography
- 7. Principles of Paper Chromatography • Capillary Action – the movement of liquid within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension. • Solubility – the degree to which a material (solute) dissolves into a solvent. Separation of components depends on both their solubility in the mobile phase and their affinity to the mobile phase and the stationary phase.
- 8. Questioned Documents PRE-LAB 1. Read and Highlight pages 1 & 2 2. For each individual step in the procedure make an illustration and notes in the margin of the lab pages. Pre-lab must be completed before you start your experimentation.
- 10. Glass Beaker Glass Rod Water - below the ink dot!!!!!! Ink Dot Paper Strip You will need 6 strips of paper, one for each pen.
- 11. Paper Chromatography Experiment Station 4 make sure your set-up is just like figure 1
- 14. 1.Liquid Chromatography Used to identify unknown plant pigments & other compounds. 2.Thin-Layer Chromatography Uses thin plastic or glass trays to identify the composition of pigments, chemicals, and other unknown substances. Examples of Chromatography
- 15. More Examples 4.Paper Chromatography Can be used to separate the components of inks, dyes, plant compounds (chlorophyll), make- up, and many other substances 3.Gas Chromatography Used to determine the chemical composition of unknown substances, such as the different compounds in gasoline shown by each separate peak in the graph below.
- 16. Mixtures & Compounds Mixture – Two or more substances that are mixed together, but not chemically combined. Examples of mixtures ... Air – mixture of gases Bowl of cereal – mixture of cereal and milk Soda pop – mixture of soda syrup, water, and CO2 gas Fog –water suspended in air Kool-Aid – mixture of water, sugar, and flavor crystals Examples of compounds ... Salt –Sodium and chlorine combined chemically Water –Hydrogen and oxygen combined chemically Carbon Dioxide – Carbon and oxygen combined chemically Compounds – Two or more elements that are chemically combined.
- 17. Definition of Chromatography Detailed Definition: Chromatography is a laboratory technique that separates components within a mixture by using the differential affinities of the components for a mobile medium and for a stationary adsorbing medium through which they pass. Terminology: • Differential – showing a difference, distinctive • Affinity – natural attraction or force between things • Mobile Medium – gas or liquid that carries the components (mobile phase) • Stationary Medium – the part of the apparatus that does not move with the sample (stationary phase)
- 18. Explanation: • Compound is placed on stationary phase • Mobile phase passes through the stationary phase • Mobile phase solubilizes the components • Mobile phase carries the individual components a certain distance through the stationary phase, depending on their attraction to both of the phases Definition of Chromatography
- 19. Overview of the Experiment Purpose: To introduce students to the principles and terminology of chromatography and demonstrate separation of the dyes in Sharpie Pens with paper chromatography. Time Required: Prep. time: 10 minutes Experiment time: 45 minutes Costs: Less than $10
- 20. • 6 beakers or jars • 6 covers or lids • Distilled H2O • Isopropanol • Graduated cylinder • 6 strips of filter paper • Different colors of Sharpie pens • Pencil • Ruler • Scissors • Tape Materials List
- 21. Preparing the Isopropanol Solutions • Prepare 15 ml of the following isopropanol solutions in appropriately labeled beakers: - 0%, 5%, 10%, 20%, 50%, and 100%
- 22. Preparing the Chromatography Strips • Cut 6 strips of filter paper • Draw a line 1 cm above the bottom edge of the strip with the pencil • Label each strip with its corresponding solution • Place a spot from each pen on your starting line
- 23. Developing the Chromatograms • Place the strips in the beakers • Make sure the solution does not come above your start line • Keep the beakers covered • Let strips develop until the ascending solution front is about 2 cm from the top of the strip • Remove the strips and let them dry
- 27. Observing the Chromatograms Concentration of Isopropanol 0% 20% 50% 70% 100%
- 28. Black Dye Concentration of Isopropanol 0% 20% 50% 70% 100% 1. Dyes separated – purple and black 2. Not soluble in low concentrations of isopropanol 3. Partially soluble in concentrations of isopropanol >20%
- 29. Blue Dye Concentration of Isopropanol 0% 20% 50% 70% 100% 1. Dye separated – blue 2. Not very soluble in low concentrations of isopropanol 3. Completely soluble in high concentrations of isopropanol
- 30. Green Dye Concentration of Isopropanol 0% 20% 50% 70% 100% 1. Dye separated – blue and yellow 2. Blue – Soluble in concentrations of isopropanol >20% 3. Yellow – Soluble in concentrations of isopropanol >0%
- 31. Red Dye 1. Dyes separated – red and yellow 2. Yellow –soluble in low concentrations of isopropanol and less soluble in high concentrations of isopropanol Concentration of Isopropanol 0% 20% 50% 70% 100% 3. Red – slightly soluble in low concentrations of isopropanol, and more soluble in concentrations of isopropanol >20%
- 32. Alternative Experiments • Test different samples: – Other markers, pens, highlighters – Flower pigments – Food Colors • Test different solvents: – Other alcohols: methanol, ethanol, propanol, butanol • Test different papers: – Coffee filters – Paper towels – Cardstock – Typing paper
- 36. TEKS Standards • 6.1, 7.1, 8.1 Student conducts laboratory investigations using safe, environmentally appropriate, and ethical practices. • 6.2, 7.2, 8,2 Student uses scientific inquiry methods during laboratory investigations. • 6.3, 7.3, 8.3 Student uses critical thinking and scientific thinking and problem solving to make informed decisions. • 6.4, 7.4, 8.4 Student knows how to use a variety of tools and methods to conduct science inquiry. • 6.7 , 7.7, 8.9Student knows that substances have physical and chemical properties.