Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances. - PowerPoint PPT Presentation

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Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances.

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Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances. Chromatography can be used to identify drugs, poisons and ... – PowerPoint PPT presentation

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Title: Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances.


1
  • 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

2
  • 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

3
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

4
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)

5
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

6
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.

7
Paper Chromatography of Ink
  • Two samples of black ink from two different
    manufacturers have been characterized using paper
    chromatography.

8
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.

9
Solve for Rf
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