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Cards In This Set
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Outline the general steps in preparing a developing chamber
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1) Line inside of 100 mL beaker with large precut half moon shaped filter paper, straight edge down, leaving at least 1nch open for viewing of plate
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What is the purpose of this liner? 2 reasons
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1)The purpose of this liner is to saturate the chamber with vapours of the developing solvent, thus reducing its evaporation from the TLC plate
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What is the purpose of this liner? 2 reasons
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2) Also it maintains the rate of the irrigation process
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Outline the general steps in preparing a developing chamber
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Prepare the developing solvent outside this beaker and pour 5-8 mL of it into the developing chamber
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What do we do if the compound under investigation is extremely polar? How does this affect the developing chamber?
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We have to add a few drops of aacetic acid into the developing chamber before putting the TLC plate in.
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If our compound under investigation is extremely polar, why do we add acetic acid to developing chamber?
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Acetic acid will increase polarity of the developing solvent and will reduce amount of attraction these polar compounds have for stationary phase
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If our compound under investigation is extremely polar, why do we add acetic acid to developing chamber?
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This would reduce the amount of streaking or tailing these compound would normally display on the developed plate
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Outline the general steps in preparing a developing chamber
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Cover the beaker with a watchglass and let it stand at least 5 minutes before you put a plate in for developing
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How do we make spotting solutions?
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Make 10% solutions of compounds. Place few crystals on end of spatula and put into small test tube. Then dissolve in min. amount (4-5 drops)
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What is our TLC plate made off?
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It is coated with silica gel that has been pretreated with a fluorescent dye
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How do we prepare our TLC plate?
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Use pencil and draw faint lines 1cm from bottom and top of plate. Do not break surface of adsorbent material.
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How do we prepare our TLC plate?
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On bottom line, place one small dot for each compound to be investigated equidistant from each other. Do not touch area between 2 lines with fingers
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How do we preform the spotting step of this procedure?
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Dip micropipet into spotting solution. Touch the TLC plate on the dot and allow liquid to spread to a 2mm diameter. Allow spot to dry.
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How do we perform the development/ irrigation step?
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Dip lower end of prepared plate into developing chamber and cover with watchglass.
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How do we perform the development/ irrigation step?
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Make sure that the initial solvent level in beaker is below the spots
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