I want to do the antimicrobial activity of Stevia leaf extract, I have extracted leaf powder in various solvents in orbital shaker(2.5 g in 25ml of chloroform, ethylacetate, methanol, hexane,water) as I don't have enough sample I couldn't use the soxhlet for extraction.
Now the paper I'm referring says I have to prepare aliquotes from stock solution of 100mg but as I have obtained less amount of extract which is sticky and possible to weigh (as its not in powder form) how would I go about preparing the stock solution
Hi Chaitra,
Weight your flask before use to be able to calculate the extract weight by excluding the weight of this flask. Then you can prepare the convenient concentration directly in this flask.
Weight the used flask before use then add the extract to the flask and evaporate the solvent completely . Leave the flask in the desiccator under vacuum overnight
then weight again the flask with the extract. Calculate the net weigh of the extract and prepare the required concentration.
Now you have sticky material which can not transfer or weight. So now you can take another pre-weight wide bottom flask (A) and take the disired solvent (like 25 ml) in other flask (B) which you want to make the stock solution. Now measure the weight of your 25 ml stock solvent and add into the vessel of extract and throughlt mix. untill all the extract get dissolve. Transfer this into flask A and measure the weight. Now you know the weight of empty flask (A), wt of solvent (25 ml), and the final concentration (i.e. extract+solvent+flask A weight). Substract the value like this
Wt of extract= Wt of final flask-(wt of empty flask(a)+ wt of solvent)
Now you can know in 25ml of solvent how much extract is present. so you can determine the concentration and can make further dilution....
Thanks
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