Lab 3: Chromatography Lab

Lab 3

Chromatography Lab

Shiva Senthil

7/18/17

Introduction

The purpose of this lab was to separate the pigments that make up different inks. To do this, filter paper was made into a wick and used to transfer water from a cup to the ink on a full piece of filter paper, and the water dissolved the ink into the separate pigments.

Questions

1. Why is it important that only the wick and not the filter paper circle be in contact with the water in the cup?

It is important that the wick is the only part in contact with the water so that the water is evenly distributed to the ink. Also, if the ink came into direct contact with the water, it may have washed off into the cup rather than dissolved on top of the filter paper.

2. What are some of the variables that will affect the pattern of colors produced on the filter paper?

Some variables are the solubility of the ink, the marks made with the ink, the locations of those marks, and the pigments the ink is made of.

3. Why does the ink separate into different pigment bands?

The ink is made of different pigments that are combined to make a mixture, and when the water comes into contact with it, the ink is dissolved and the pigments separate.

4. Choose a color present in more than one type of ink. Is the pigment that gives this color always the same? Do any of the pens appear to contain common pigments?

Blue was found in all of the inks used. The pigment is similar across the different inks because the blue pigment was one of the ingredients of black ink; however, it wasn't exactly the same as some of the time the blue was brighter while sometimes it was duller. All of the pens used typically had blue, violet, and red pigments in them to create the black ink, but different pens had slightly different shades, with the thick marker being the brightest and the normal pens being the dullest.

5. 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?

Only water-soluble markers and pens were used so that the water could dissolve the ink into the pigments. If permanent markers were used, the water could be changed to a liquid like rubbing alcohol that can dissolve permanent markers.

A picture of the final result of the dissolved ink.