chromolab
Chemistry 100 Experiment #2: Chromatography of Food Dyes
Name: Cassandra DeVaux Date: April 17, 2014
Purpose:
To learn how mixtures of compounds can be separated and what food dyes are found in certain foods
Introduction: In this exercise we will separate food dyes from a variety of sources. We will first gather data on known dyes where we know how many substances make up the dye. Then we will collect data on some samples where we do not know the make-up. We will compare our known dyes with our unknown samples and be able to make a determination of which dyes are in our unknown samples.
Chromatography is a technique used to separate substances dissolved in a mixture. Chromato means color and graphy means “to write.” Paper is the medium used to separate the components of the mixture. Our known substances will be FD&C dyes that are used in food products. Currently, there are seven approved food dyes. These are:
Red 3
Red 40
Blue 1
Blue 2
Yellow 5
Yellow 6
Green 3 (**will not be used in this lab) To determine the components of our unknown, we will calculate the retention factor (Rf) of each spot. The Rf is a unitless mathematical expression for the distance traveled by the dye molecules divided by the distance traveled by the solvent front. The Rf factor will be constant for a given dye provided all conditions in the experiment are kept constant. distance travelled by dye
Rf = --------------------------------------- distance travelled by solvent
Data for Sheet 1:
1. Using the drawing function on your word processer, draw a picture of your chromatography sheet once the dots are applied, but before you have set it into the solvent. (you can also take a picture and insert it here)
2. Using the drawing function on your word processor, draw a picture of your chromatography sheet once the experiment is over. Mark the solvent line and
Name: Cassandra DeVaux Date: April 17, 2014
Purpose:
To learn how mixtures of compounds can be separated and what food dyes are found in certain foods
Introduction: In this exercise we will separate food dyes from a variety of sources. We will first gather data on known dyes where we know how many substances make up the dye. Then we will collect data on some samples where we do not know the make-up. We will compare our known dyes with our unknown samples and be able to make a determination of which dyes are in our unknown samples.
Chromatography is a technique used to separate substances dissolved in a mixture. Chromato means color and graphy means “to write.” Paper is the medium used to separate the components of the mixture. Our known substances will be FD&C dyes that are used in food products. Currently, there are seven approved food dyes. These are:
Red 3
Red 40
Blue 1
Blue 2
Yellow 5
Yellow 6
Green 3 (**will not be used in this lab) To determine the components of our unknown, we will calculate the retention factor (Rf) of each spot. The Rf is a unitless mathematical expression for the distance traveled by the dye molecules divided by the distance traveled by the solvent front. The Rf factor will be constant for a given dye provided all conditions in the experiment are kept constant. distance travelled by dye
Rf = --------------------------------------- distance travelled by solvent
Data for Sheet 1:
1. Using the drawing function on your word processer, draw a picture of your chromatography sheet once the dots are applied, but before you have set it into the solvent. (you can also take a picture and insert it here)
2. Using the drawing function on your word processor, draw a picture of your chromatography sheet once the experiment is over. Mark the solvent line and