1. STEM Electrophoresis with Food Dyes
Bio-Rad Biotechnology Explorer IDEA and STEM Kits

2. Materials to be Separated Property Used to Separate Components
Separation technology: How do you separate two or more compounds from each other?
Materials to be Separated
Property Used to Separate Components
Explanation
Iron filings from other metals
Magnetism
Iron filings will be attracted to a magnet while other metals will not
Salt from sand
Solubility
Salt will dissolve in water and can be separated from the sand
Caffeine from coffee beans
A solvent is used that selectively dissolves the caffeine (such as dichloromethane or ethyl acetate) but not most of the remaining coffee oils
Ethanol from fermented grain
Boiling point
Ethanol will boil off at a lower temperature than the other components of the fermented grain
Wheat from chaff
Density
Wheat kernels are more dense and will fall to the ground while chaff can be blow away by the wind
Tea from tea leaves
Size
Filtration can be used to separate the liquid extract from the large tea leaves

3. Electricity can be used to separate molecules by charge
Acetate ions
Tris ions -
HO CH2 C CH2 OH
NH3+
CH2 OH +
CH C O O- + -
Apply an electrical charge

4. Sieves can be used to separate materials by their size

5. Electrophoresis separates molecules by CHARGE and SIZE
Electrophoresis means “to carry with electricity”
Molecular sieve
Electricity

6. Food dyes – What have you recently eaten?…
Did you eat any cheddar cheese? Was it orange?
Starbucks Strawberry Frapuccino?

7. FD&C Dyes and Natural dyes
FD&C Synthetic Dyes
FD&C Red 40 or FD&C Red 40 Lake
FD&C Yellow 6 or FD&C Yellow 6 Lake
FD&C Yellow 5 or FD&C Yellow 5 Lake
FD&C Blue 1 or FD&C Blue 1 Lake
FD&C Blue 2 or FD&C Blue 2 Lake
FD&C Red 3 or FD&C Red 3 Lake
FD&C Green 3 or FD&C Green 3 Lake
Natural Dyes
Beetroot red or betanin (from beets)
Curcumin (from tumeric)
Caramel coloring (from sugar)
Annatto (seeds of achiote trees)
Carminic acid, carmine, or cochineal (from ground up beetle abdomens)
Lycopene (from tomatoes, watermelons, papayas, and red carrots)

8. Food dyes in the news

9. Food dyes have an intrinsic SIZE and CHARGE and thus can be separated using Electrophoresis
Molecular weight
Charge
FD&C Blue 1
792.86 -2
FD&C Yellow 5
534.37 -3
FD&C Yellow 6
452.37
FD&C Red 40
496.43
Carminic Acid
492.38
Beetroot red
551.48 +1

10. So how do we design an electrophoresis chamber to separate food dyes?
Dye Electrophoresis Commercial versus built box comparisons

11. What are some of the design factors we want to think about?

12. Building and running your electrophoresis system to separate the dyes

13. Building and running your electrophoresis system to separate the dyes

14. Building and running your electrophoresis system to separate the dyes

15. Building and running your electrophoresis system to separate the dyes

16. Building and running your electrophoresis system to separate the dyes

17. Extensions Copper electrode Electrochemistry study
pH changes at the cathode and anode
Effect of material choice for electrode
Optimization of STEM box system
Electrode material choice and thickness
Different materials for gel thickness
Impact of TAE Concentration and Volume
Gel percentages
Gelatin matrix