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CHROMATOGRAPHY

CHROMATOGRAPHY. ENVE 202 Dr. Aslıhan Kerç. Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances. Chromatography can be used to identify drugs, poisons and many other substances. Separation is determined by the molecular size and/or charge.

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CHROMATOGRAPHY

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  1. CHROMATOGRAPHY ENVE 202 Dr. Aslıhan Kerç

  2. Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances. Chromatography can be used to identify drugs, poisons and many other substances. Separation is determined by the molecular size and/or charge

  3. http://members.shaw.ca/vict/chemistry_test3.htm What is chromatography? Chromatography (from Greek word for chromosfor colour) is the collective term for a family of laboratory techniques for the separation of mixtures. It involves passing a mixture which contains the analyte through a stationary phase, which separates it from other molecules in the mixture and allows it to be isolated. Which means ... Chromatography is the physical separation of a mixture into its individual components.

  4. All forms of chromatography involve 2 phases • The Two Phases • 1. stationary (absorbent) phase • the material on which the separation takes place • 2. mobile phase - the solvent transports the sample • Types of Chromatography - 5 of them

  5. Separation • A sample is often a mixture of many components in a complex matrix. • The components must be separated from each other so that each individual component can be identified by other analytical methods. • The separation properties of the components in a mixture are constant under constant conditions. • Once determined they can be used to identify and quantify each of the components. • A mixture can be separated using differences in physical or chemical properties of the individual components.

  6. In chromatography • A column holds the stationary phase, and the mobile phasecarries the sample through it. • Sample components that partition strongly into the stationary phasespend a greater amount of time in the column and are separated from components that staypredominantly in the mobile phase and pass through the column faster.

  7. Chromatograms • If a detector that responds to solute concentration is placed at the end of the column and its signal is plotted as a function of time, a series of symmetric peaks is obtained. • The positions of the peaks on the time axis is used to identify the components of the sample. • The areas under the peaks provide a quantitative measure of the amount of each species.

  8. Gas Chromatography Gas Chromatography • a gas separates the components • they are then ionized and an electrical signal is recorded • mobile phase - carrier gas • stationary phase - thin film of liquid

  9. HPLC • High Performance Liquid Chromatography (HPLC) • - done at room temp. - advantageous for chemicals that are heat sensitive or volatile - example LSD • - a liquid (mobile phase) is pumped through a column containing fine particles (stationary phase)

  10. TLC • Thin - Layer Chromatography (TLC) • -A plate is coated with a granular gel - usually silica gel or aluminum oxide (stationary phase) • - the substance to be separated is carried up the plate by capillary action - the substance with most affinity for the plate will rise the farthest. • 4. Paper chromatography • Same as TLC but paper • is used as stationary phase

  11. Electrophoresis • Electrophoresis • - Similar to TLC but the substance is separated through a gel by electric current • - Due to different size and charge substances will move across the plase at different speeds.

  12. Paper Chromatography of Ink Two samples of black ink from two different manufacturers have been characterized using paper chromatography.

  13. Retention Factor (Rf) • A number that represents how far a compound travels in a particular solvent • It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.

  14. Solve for Rf

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