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    Paper Chromatography

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    Experimental Procedure
    1. Obtain the following items:
    a. 600 ml Beaker
    b. A no. 2 lead pencil with a sharp point
    c. A ruler graduated in centimeters
    d. 2 sheets of 20lb. white copy paper
    e. Food dyes (food coloring)
    i. Red
    ii. Blue
    iii. Yellow
    iv. Green
    f. Eluting solvents of varying polarity
    i. Isopropyl alcohol (rubbing alcohol)-low polarity
    ii. Tap water/Isopropyl Alcohol (50/50 mixture)-medium polarity
    • Plastic wrap
    • Stapler
    • Round tooth pick with a fine point
    2. Cut the copy paper 24 cm long x 12 cm high. Draw a straight line (across the long dimension) 1 cm above the edge of the paper using a number 2 lead pencil.
    3. Place equally spaced dots onto the sample line with the number 2 pencil. Label the spots as R for red, B for blue, Y for yellow, G for green, O for orange, P for purple, and K for black.
    4. To make the orange dye, mix equal drops of red and yellow dyes. To make the purple dye, mix equal drops of red and blue dyes, and to make the black dye mix equal drops of all the dyes.
    5. Put drops of each dye on a flat surface.
    6. Begin 1cm from the left hand edge of the paper and using a fine point, place small amounts of each dye on the spots on each of the two chromatography sheets.
    7. Let the sample spots dry. Fold the sheets into cylinders making sure the edges don't overlap, and staple the edges together - top, middle, and bottom.
    8. Place a minimum amount of the eluting solvent into the 600ml beaker. Be sure the depth is below the sample spot line.
    9. Set the paper cylinder into the beaker with the sample spot line above the liquid level.
    10. Cover the container to retain solvent vapor inside the chromatography container (beaker).
    11. Let the solvent advance up the chromatography paper until it is within a 0.50 inch of the top of the paper, or as high as it will go.
    12. The isopropyl / water solvent will advance to roughly half of the height.
    13. Remove the cylinder from the container, open it up, lay the sheet flat on pieces of absorbent paper towels and draw a line (#2 pencil) across the solvent front.
    14. Measure the distance from the sample spot line to the mid-point of each color spot.
    15. *Compute the Rf values for the components of each spot and record them in the space below.
    16. Repeat steps 2-13 using a 50/50 mixture of water and isopropyl alcohol as the solvent.
    Solvent

    Substance
    Isopropyl
    Alcohol
    Water/Isopropyl
    Mixture
    Yellow Dye Rf = spot distance
    Solvent front distance
    Blue Dye
    Red Dye

    Orange Dye
    Purple Dye
    Black Dye

    Based on the Rf values of the different dyes and mixtures in the less polar (isopropyl) and the more polar (mixture), answer the following questions about dyes.
    1. Which dye is the most polar?

    2. What two components are found in the green dye?

    3. Which dye is the second most polar dye?

    4. Which dye has large Rf values in both solvents?
    a. Is this dye polar? Yes or No?
    b. Is this dye non polar? Yes or No?
    c. Is this dye attracted to the stationary phase? Yes or No. Explain.

    © BrainMass Inc. brainmass.com October 10, 2019, 6:37 am ad1c9bdddf
    https://brainmass.com/chemistry/general-chemistry/paper-chromatography-550434

    Attachments

    Solution Preview

    The data in the table is considered hypothetical data. You have to actually do the paper chromatography experiment in order to get the exact data.

    The data in the table is an example of how the paper chromatography lab would works.

    Paper chromatography is a method of separating an unknown compounds, and identifying the polarity of the compounds based on its Rf values. (1) It has both a stationary phase and a mobile phase. The stationary phase is the filter paper, and the mobile phase is the liquid solvent that travel up the stationary phase carrying the unknown compounds. (1)

    Experimental Procedure
    1. Obtain the following items:
    a. 600 ml Beaker
    b. A no. 2 lead pencil with a sharp point
    c. A ruler graduated in centimeters
    d. 2 sheets of 20lb. white copy paper
    e. Food dyes (food coloring)
    i. Red
    ii. Blue
    iii. Yellow
    iv. Green
    f. Eluting solvents of varying polarity
    i. Isopropyl alcohol (rubbing alcohol)-low polarity
    ii. Tap water/Isopropyl Alcohol (50/50 mixture)-medium polarity
    - Plastic wrap
    - Stapler
    - Round tooth pick with a fine point
    2. Cut the copy paper 24 cm long x 12 cm high. Draw a straight line (across the long dimension) 1 cm above the edge of the paper using a number 2 lead pencil.
    3. Place equally spaced dots onto the sample line with the number 2 pencil. Label the spots as R for red, B for blue, Y for yellow, G for green, O for orange, P for purple, and K for black.
    4. To make the orange dye, mix equal drops of red and yellow dyes. To make the purple dye, mix equal drops of red and blue dyes, and to make the black dye mix equal drops of all the dyes.
    5. Put drops of each dye on a flat surface.
    6. Begin 1cm from the left hand edge of the paper and using a fine point, place small amounts of each dye on the spots on each of the two chromatography sheets.
    7. Let the sample spots dry. Fold the sheets into cylinders making sure the edges don't overlap, and staple the edges together - top, middle, and bottom.
    8. Place a minimum amount of the eluting solvent into the 600ml beaker. Be sure the depth is below the sample spot line.
    9. Set the paper cylinder into the beaker with the sample spot line above the liquid level.
    10. Cover the container to retain solvent vapor inside the ...

    Solution Summary

    The two components found in green dye are determined by using paper chromaography. The dye which is the second most polar is determined.

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