Objective Statement: In this lab, you will use your designed extraction method to extract lycopene from tomato paste. Using two provided laboratory technique papers, and the availability of several solvents, create and proceed through your own built laboratory technique. TLC and UV-vis analysis will be conducted to determine the purity and effectiveness of your lab procedure. A final comparison of the different procedures produced by my lab mates to determine the best technique for extraction.

Lycopene

Polarity: non-polar

Mass:536.78 g/mol

MF: C40H56

Density: 0.889 g/cm3

BP: 660.9 °C

MP: 177°C

Solubility: Soluble in benzene and ethyl ether. Insoluble in water and ethanol

Pre-Lab Questions:

What procedure will you use to isolate the lycopene from your tomato paste? As part of your procedure, you need to exactly specify the solvent system you will use to prepare the paste and the amount of each solvent(s). You will use 12 grams of tomato paste which is about the equivalent of 3 g of dry material.

12 grams of tomato paste in 15 mL of acetone mix thoroughly for 3-4 minutes to remove all water and all water-soluble substances.
Decant liquid and squeeze paste in filter paper to remove excess liquid.
Put the dehydrated paste into a 1:1 mixture of 15 mL of pet ether and dichloromethane, and stir for 3-4 minutes.
Add a small scoop of magnesium sulfate to remove any last traces of water.
Gravity filter tomato, pet ether: dichloromethane mixture.

Procedure:

Pre-lab notes:
- you will need to boil the tomato paste for a time in a solvent. The kind of boiling that you will be doing is known as refluxing. it is not just a simple boil and you can look it up while you are researching methods
- when cool, the contents of your flask will go into a separatory funnel and you need to isolate the non-polar fraction.
- you will need to end the procedure with solid lycopene.
- You also must include all results such as Rf values and a list of the major UV peaks including approximate wavelength and intensity. This is the data that you use to draw concluding statements from. The UV vis and TLC can be completed before you evaporate your solvent.
- Product should be evaporated to dryness by the following lab period so that you can determine % recovery based on mass. write as many conclusions and reflections as possible from the data collected so that you only have to add a few additional notes regarding the mass recovered.
- You will need to obtain results from two other groups and compare your results to theirs. In your discussion and conclusion section, you must compare the differences in your procedures to that of the other groups, the differences in the amount of lycopene collected, and then draw conclusions about your opinion about the best way to isolate lycopene.

Experiment 1

Obtained 12g of tomato paste and mixed in a breaker with 100 mL of a 1:1 mixture of ethyl acetate and hexane.
Transferred solution into a two-neck round bottom flask for refluxing.
Bring the solution to a boil at 45 degrees Celsius for 35 minutes.
Remove the double-necked round-bottom flask and let it cool to room temperature.
Used gravity filtration to remove the tomato paste from the liquid. After all the liquid has gone through the gravity filtration system, pick up filter paper and squeeze the last bit of liquid out of the paste. Do not squeeze or fold too hard, run the risk of ripping the filter paper.
Transferred the filtered lycopene into a 150 mL separatory funnel, added 50 mL of water, and inverted the funnel 15 times, releasing pressure very five inversions.
Separated the bottom aqueous layer from the top colored layer.
Added a significant amount of magnesium sulfate to the organic layer until the magnesium sulfate did not clump together and instead swirled freely. Removed the last bit of water in the solution.
Vacuum filtrated the magnesium sulfate out of the organic layer.
Liquid was placed on a heating mantle under vacuum pressure to isolate lycopene.
Lycopene was collected and analyzed with TLC and a UV/Vis machine.

Observations

The paste caused the clear solvent to turn a dark orange color and released an orange/yellow vapor when refluxing in the round bottom flask.
An orange ring layer formed around the bottom of the flask after 35 minutes of refluxing.
Distinct orange top layer in separatory funnel after inversions.

Results:

Solvent System: 9:1 hexane/ethyl acetate

No standard so only spot hights

Rf = 3.4 cm/ 4.0 cm = .85

Max wavelengths: 419.62 nm, 439.52 nm, and 469.24 nm

.085 grams of solid lycopene collected
- (.085g extracted lycopene/.2g expected) x 100% = 42.5%
- Recovery of other groups: 0% and 45%

Conclusion/Discussion:

With a percent yield of 42.5%, this experiment was decently successful. Along with wavelengths in the range of 400nm - 500nm, within the literature value of 300nm - 600nm for lycopene, effective extraction and purification of lycopene were achieved. Without a standard for TLC, only a comparison of the two tests also supports the proper extraction of lycopene. Mass Spectrometry analysis was a little lower than expected. The reported value of lycopene should be around 536 m/z. Our sample was sitting at a value of around 491.3 m/z. Along with a lower percent yield than anticipated, boiling at too high of a temperature can be an explanation for these results.

Reflection:

I was more prepared for this lab. I did a lot more research outside of the provided articles to make sure I understood all the components of the experiment and what I was trying to achieve before the class started. Refluxing was a technique I learned, but understood and with my prior knowledge, I feel like my group and I had success in experimenting. One thing I would improve upon for the next lab is to make sure to check in with my instructor throughout the lab. We boiled our lycopene at a much higher temperature than it should have been refluxing, resulting in a lower percent yield than expected. Having more input or instructions from our instructor would have been a little more helpful since the articles were a little advanced for our scientific language and understanding and it was confusing to navigate through.