Badria Al-Battashy you can measure flavonoid content following the protocol mentioned in this article. There we used Quercetin as standard but you can use rutin in same way in same amount as standard. Thanks.

Article Preliminary pharmacological evaluation of Alocasia indica Schott tuber

you can measure flavonoid content by gc ms that is very easy

Thanks Thamere Cheriet

Sanjib Saha, is it okay to use the procedure you proposed for an ethyl acetate extract instead of ethanol?

Badria Al-Battashy Yes, you can use the procedure for ethyl acetate extract. It does not matter which solvent you use for extraction because you are evaporating the solvent after extraction. Therefore, any solvent works for the extraction. For doing the experiment, you can dissolve the dried extract in ethanol or methanol or whtever solvent you can dissolve extract and chemicals. Remember to use appropriate blank of your solvent. Thanks.

Thanks again Sanjib Saha

Sanjib Saha , How much of the solutions from the flask is kept in the UV cell, is the same solvent used again to fill up the UV cuvette after solution or just the flask solution itself? To put it in another way, is the concentration of the standard solutions mentioned in your procedure same as the one in the calibration curve or there is further dilution by solvent in the cuvette? If there is dilution please tell me how i find the actual concentration to write in the curve for the analysis. I would be much grateful if you can help me with this.

Badria Al-Battashy You make your stock and dilute them separately to make your all sample for standard curve. Then take each of them in UV cell for measurement. You don't need to dilute in UV cell. Before taking each measurement wash it with blank sol or the sample itself to remove previous sample carryover. If I didn't answer your question correctly please remind me exactly what you want to know. Thanks.

Thank you very much Sanjib Saha