Chromatography is a simple and useful analysis method used in chemistry and biochemistry. the method separates a mixture by running them through a solution, in which the different components of the mixture will move at different rates. In this instructable you will preform the analysis on candy and see the different components of the dye on the candy's outer shell separate.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Gathering Materials
For this instructable you will need:
- skittles or M&Ms candy (one of each color)
- coffee filter paper
- a clear glass or cup
- 3 cups of water
- 1/8th teaspoon of salt
- pencil (no pens or markers, they will bleed with the solution)
- toothpicks for each color
- aluminum foil
Step 2: Preparing the Paper
- cut a coffee filter into a 3 inch by 3 inch square. It is best to flatten the coffee filter before cutting to get a flat even paper. (see figure 2)
Step 3: Dotting the Paper
- at one edge of the paper, draw a line 1/2 an inch above the end of the paper. on this line mark 5 dots to represent the number of different colors that are being tested.(see figure 3) (NOTE: may be more or less depending on the number of colors).
- give some space on the sides of the paper and between each dot to ensure the colors will not bleed into each other.
- label each dot with the color it will represent. I used R for red, G for green, O for orange, Y for yellow and P for purple.
Step 4: Preparing the Candy Dye
- get a strip of foil and put 5 dots of water on it, well spaced out so they will not touch.
- put a skittle on top of each and let it sit for a minute. the dye will bleed off of the candy.
NOTE: I also put a drop of water on top hoping to get a more concentrated dye for each candy.
Step 5: Preparing the Solution
- to prepare the solution combine 3 cups of water with 1/8th teaspoon of table salt. this creates a 1% salt solution to carry the dye.
- be sure to stir the solution until the salt has fully dissolved
Step 6: "Spotting" the Paper
- spotting refers to the technique use to put a small little dot on the paper when performing chromatography.
- to spot the dye on the paper, take the toothpick and dip it in the dye. then lightly dab it onto the respective spot on the paper. (see Figure 6)
- the smaller the radius of the dot the better, ideally around 1/16th of an inch.
- do this for all the different dyes available on their respective spots. the final product should look something like in Figure 7.
Step 7: Running the Experiment
- fill the empty glass or container with about 1/4th an inch of the solution.
- next put the paper into the solution. the bottom of the paper should be submerged, but the waterline must not touch the line or dots. (see Figure 8) (NOTE: I recommend folding the paper in half, this way it will stand in the solution and not fall over. it is important that it stays upright the entire time.)
- now watch the solution climb through the filter paper. the amount of time this may take can vary.
- once the solution has climbed till there is only 1/4th of an inch of space left at the top remove the paper and allow it to dry.
- once it is dry the results should be clear and you can see the different colors of each dye (see Figure 9)
NOTE: I recommend folding the paper in half, this way it will stand in the solution and not fall over. it is important that it stays upright the entire time.