Actually, I'm trying to extract Spirulina microalgae using ethyl acetate to evaluate antioxidant activity. I want the ethyl acetate to be 50% diluted, meaning that I'm planning to add 50 ml water into 50ml of ethyl acetate. Is this applicable, because ethyl acetate has a low solubility in Water? Will this work?
You can try any solvent, or mixture of solvents that allow you to do the extraction. It is important that this solvent will allow you to use the antioxidant's assay. The determination of the antioxidant properties insists to subtract the effect of the solvent from the effect of the solution. Bare in mind that you have to determine the instrumental error of determination of the measured antioxidant marker.
If it was me I would proceed this way"
1- I will make sure that the extraction is complete.
2- I will use the antioxidant assay on the solvent used for my extraction. I will determine the instrumental error of determination of the antioxidant marker, using my solvent.
3- If the assay works with my solvent, I will perform this assay on my solution, containing the dissolved antioxidant.
I wich you luck:)
It doesn't realy make sense to use a mixture of ethyl acetaten and water as you wil get phase separation and some of the antioxidants will be in the ethyl acetate layer , whereas others will be in the aqueous phase. If you want to alter the polarity, it is better to use water/alcohol (ethanol of methanol) mixtures.
I do agree with Koen goiris.....for me i do extraction for some plant hormones and I do extract them in 100% Ethyl-acetate. Yes, to alter the polarity u may try methanol or ethanol aqueous solutions...
Why do you want to dilute the ethyl acetate? If you want to increase polarity you should use a different solvent completely or add a non-ethyl acetate-immiscible solvent to your ethyl acetate. I would suggest that you attempt the extraction with several different solvents/solvent combinations and then test the antioxidant activity to determine the best one.
its btr 2 use ethyl acetate without dilution 2 avoid any prblm. As far as antioxidants r cncrned u can use ethanol as it dissolves LMWA (low molecular weight antioxidants).
I think that the using a mixture of ethyl acetaten and water as you wil get phase separation and some of the antioxidants will be in the ethyl acetate layer , whereas others will be in the aqueous phase.
Yes Koen is correct. However, if the spirulina is in the form of wet biomass the ethyl acetate will not extract compounds as efficiently as when it's dry-for the same reason: it's immiscible with water. If you want to extract antioxidants I suggest you start with water, or a water:ethanol mixture, then pure ethanol and proceed to a less polar solvent, so that you don't get phase separation. Most anti-oxidants will be in the water, water-ethanol and ethanol extracts. You can vary the extraction time and temperature at each step. n-butanol and iso-butanol are also effective solvents but have a higher bp than water so are more difficult to evaporate off. There's a lot of open peer-reviewed literature on extraction of antioxidants from Spirulina.
When extracting plant material with ethyl acetate it is better to saturate it with water. If you use dry ethyl acetate the first thing that will happen is that it will extract water from the plant tissue to reach saturation point. Since extraction properties of dry vs. ethyl acetate/water are different this behaviour will only complicate matter when you try to understand what you are extracting.
Saturating ethyl acetate with water is easy you add some water to the ethyl acetate and you stir quiet vigorously. As long as the ethyl acetate isn't saturated the water will mix with the solvent. Ones saturated you get phase seperation. At room temperature "moist"ethyl acetate contains about 3 % water.
Hi,
some of above answers were good and don't mix with water. Better you choose other solvent system with similar polarity that you require. It's very difficult to remove from the product and undergoes trans-esterification, becomes toxic.
Otherwise you can opt for 'tert-butyl-methyl ether' and try other solvent systems. Screen for relative activity in different solvent systems.
Good Luck...!!
Dear all, thank you so much for the suggestions.I really appreciate It.
We normally screen solvents of different polarity, that is from water till hexane, to determine which actually contain highest antioxidant activity. Ethyl acetate, according to my experience is it has never shown highest antioxidant activity for the few plants tested.
For antioxidant compounds, usually we use ethanol 80% first, and then we screened to separate non polar, semi polar layer. I agree that the highest antioxidant activity usually in polar layer.
It is unsusal to use ethylacetate as a extraction solvent. You may use it in the fractioation of the crude extract to make an ethylacetate fraction. Nevertheless, it is inadvisable to dilute it.
Its btr to go ahead with methanol or ethanol to evaluate antioxidant activity as it extracts low molecular weight antioxidants. Another approach can be to extract the sample in the above two solvents separately and then sequentially extract with ethyl acetate which can be a flavonoid rich fraction. U can compare the results of all the modifications and get to the final conclusion.
Do not dilute Ethyl Acetate.Instead use Ethanol or Methanol.
the answer is no, since ethyl acetate is immiscible with water. So, you can't dilute it with water. You can just clean it from other solvents or pollutants through distillation.
I suggest to use methanol as a solvent for extraction instead of ethyl acetate since ethyl acetate doesn't dissolve some polar phenolic compounds.
You can mix with methanol/ethanol in different ratios with Ethylacetate and use for extraction
Ethylacetate has concentrating effect on flavonoids and phenolic compounds generally, but extracting the flavonoids or phenolic compounds are better with methanol. you may then partition the extract between ethylacetate and water for better resolution.
The answer yes or no depend your objective , the bettter way to validade verify your hytothesis can be via theorical caculation based on solublity parameters of polarity properties of solvent wihch can be estimated for mixed solvents .
The answer can be no , evident water is not good solvent , yet mixed solvent effect can be little less as you wished , thus can be ye acording to your hypothesi . instead water a well Chinwe Sylvanus Alisi idea instead 2 stagess you can use co solvent approaches of maximization of bioactive extractation as well well as concentration insttead 2 stages increased effort , investment cost as ugested by Chinwe Sylvanus Alisi by sing stage as per your your best approach with good biovision in single stage . instead trial and error experimental you can jose cosolvent based on Chinwe Sylvanus Alisi data here methanol is better solvent , , then to arive it same value of solublity , you can mix as you wish ethylacetate, water any other cheaper solvents such as ethanol , hexane , later validade this co solvent via less experimental study . This co solvent was indeed i have done on organosolve delignification simillar your problem of polyphenolics , indeed lignin are ver very high polymer of diferents aromatics phenolics , unlike known polmers chemistry well known to us with single monmers.wish you all the best and sucess too
Dr. Pagandai Vaithianathan Pannirselvam, noted.
Actually as you said I did tried with all different solvents. I used Methanol, 50% diluted methanol, ethyl acetate, hexane and distilled water to extract phenolic compounds separately and made comparison. And Yes as suggested methanol was very productive compared to other solvents. Thank you for the suggestions.
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