🎈 Public Lab: Lycopene extraction attempts using ethanol, ether and engine starter fluid

Lycopene extraction attempts using ethanol, ether and engine starter fluid

by iamkat | October 06, 2016 13:46 06 Oct 13:46 ... | #13528 | #13528

What I want to do

Aim: Create a DIY protocol for lycopene extraction that can use the Desktop spectrometer to identify and - hopefully - quantify the amount of lycopene extracted.

My attempt and results

Method: Test protocols with lab grade and household reagents. Run liquids through lab UV spectrometer and Desktop Spectrometer V3. 5g tomato paste, 25 ml solvent, stirred for 1 hour in a beaker, filtered through grade 1 filter paper

Test 1: Extraction using methanol - Methanol + acetic acid 1:1 5g tomato paste, 25 ml solvent - Methanol 5g tomato paste, 25 ml solvent

-- UV spectrum did not match lycopene (image coming)

Test 2: Extraction using diethyl ether. UV spectrum matched lycopene (see image). Desktop Spectrometer V3 spectrum matched lycopene, but with not so clear definition in peaks.

Test 3: Extraction using engine starter fluid (mixture of hexane and ether) UV spectrum matched lycopene (see image). Desktop Spectrometer V3 spectrum matched lycopene, but with not so clear definition in peaks.

It looks like the engine starter fluid is not as effective as the pure diethyl ether at extracting the lycopene from tomato paste.

Questions and next steps

1) Try to quantify amounts from the UV and Desktop Spectrometer spectra 2) What changes to the protocol would result in complete extraction? Is this achievable? 3) Try to purify the engine starter fluid to get pure ether - is this achievable and safe outside of a lab environment?

Why I'm interested

To generate reliable protocols that can be used to answer questions about the lycopene content in food with valid results, outside of a lab.

I'm developing these protocols as part of a much larger project looking at a multiple knowledges / subversive knowledge production approach to food, supported by the London Creative Network and UCL. The first output will be an undergraduate course in January 2017 that tests these approaches with a London community.

5 Comments

Kat,

Do you have a standard lycopene extraction? How do know what the spectrum of lycopene should look like?

Are you using a fluorescent lamp to make your extraction spectra with the Public Lab spectrometer? The lycopene peaks between 440 and 500 nm will only show up clearly if you use a continuous spectrum light source like a halogen lamp.

Have you compared these results to an extraction using just water or alcohol? These solvents will not extract all of the pigments, but might allow you to identify lycopene. Quantifying the amount of lycopene might require some other approach.

Chris

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Hi Chris, what do you mean by a standard lycopene extraction?

The UV spec of lycopene in ether can be found here http://link.springer.com/article/10.1007/s00217-006-0541-4 with three distinctive peaks at 503, 472, 445 and another at 363. My peaks are at 502, 470, 444 and 366. My sample seems to have something else in there too, perhaps another carotene.

I'm using a CFL and have calibrated to it. I wanted to use a halogen lamp but couldn't work out how to then calibrate it wrt the CFL spectrum provided. Is it explained somewhere?

I tried using water and alcohol initially - but lycopene does not dissolve in alcohol, and the UV spectrum in the lab showed it wasn't present in a filtered sample (using the methodology above). I'm looking into the quantification - someone at my lab is meant to be an expert in UV quant so I was going to ask him. If not, then perhaps trying to purify and crystallise and weigh is the best way. I've got more details of the protocol I'm going to try here https://diychemistry_food.pads.ccc.de/

Thanks,

Kat

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Thanks for the details.

After you use a CFL to calibrate the spectrometer, replace the CFL with another light source. If the spectrometer is not disturbed, you can apply the calibration to the images saved while using the other light source. I don't know whether that is explained anywhere, but I guess it should be.

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