Lab 3: Chromatography




Introduction: This report discusses how, through paper chromatography, we created patterns from a variety of black ink pens on circular pieces of paper. More specifically, this examines how ink passed through a medium, in this case, paper, in which its components move at different rates. The objective of this lab is to understand the process of how a mixture is separated and the physical properties that result from it.

Why is it important that only the wick and not the filter paper circle be in contact with the water in the cup?
If the entire filter paper were to be in contact with the water, there would be no outward radial spread of the pigments due to the lack of an origin from which water spreads. Therefore, the results that show certain pigments at further distances from the origin would be hindered.

What are some of the variables that will affect the pattern of colors produced on the filter paper?
The brand of marker used, color of marker used, type of paper used, type of marks drawn will all affect the pattern of colors produced on the filter paper. 

Why does each ink separate into different pigment bands?
The separation of pigment bands is caused by the filter paper's absorption strength for each respective pigment. Pigments that are more strongly absorbed will move along the paper slower than the solvent. Where as, pigments that are not strongly absorbed will spend more time in the solution and move along the paper at a faster rate. 

Choose one color (e.g. yellow, red, or blue) that is present in more than one type of ink. Is the pigment (compound) that gives this color always the same? Do any of the pens appear to contain common pigments? Explain. 
The color blue is often present in multiple inks and is found furthest from the origin. However, this pigment is not always the same because different inks may contain similar pigments of blue but not the same compounds. 

Why are only water-soluble markers or pens used in this activity? How could the experiment be modified to separate the pigments in "permanent" markers or pens?
The reason for using water-soluble markers in this lab was that the liquid absorbed by the wick was water. Thus, the water must be able to carry pigments that are water-soluble. If the objective of the experiment was to separate the pigments in permanent markers, we would need a liquid other than water to carry those pigments. 








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