Dear Abdollatif Sheikhi,

Thank you for your question. As expert in flavonoids analysis, I would recommend  not to determine rutin and quercetin together. Why?  because rutin= quercetin, please get back to the chemical structure of both compounds. So quercetin equal rutin, the only difference between quercetin and rutin is the presence of water molecule in rutin as rutin hydrolysed or exposed to heat lose its water molecule. So use only quercetin because it is a stable compound.  For the second question the answer is positive. You can make standard solution to each group mentioned above because each group has a certain wavelength to measure for example quercetin on 375 nm. However, you need to make a stock solution for each compound you gonna to analyse. Additionally to confirm the identification of compounds make a spectrum study for each pure compound you analyse then compare with  a compound in your sample. Finally I am attaching the method that I have developed in Queens University of Belfast-UK.

A.R. Abdel-Moemin, To investigate the antioxidant properties of dietary flavonoids in human metabolism. PhD Thesis, The Queen's University of Belfast, United Kingdom, 2004.

Good luck

Aly

Thesis Chapter 2-TO INVESTIGATE THE ANTIOXIDANT PROPERTIES OF DIETA...

Dear Abdollatif Sheikhi,

I work with antioxidants and it is possible to meassure together:

1.) alfa and gamma-tocopherols (please see Gomez et al 2008. Postharvest Biol & Tech 49: 229-234)

2.) Licopene and beta-carotene (Please see Barba et al., 2006 Food Chem 95:328-336)

Good luck and good reasearch. Regards,

Gustavo Gergoff

Dear Abdollatif, in my opinion there is no general standard commercially available. I would suggest to get all standard compounds as single compounds and then try to mix where appropriate. Some of them do not solve in the same solvent. Some of them will have different extinction coefficients, some of them need different wavelengths (does not matter if you use a DAD or MS for detection)...what was said about "quercetin=rutin" was wrong ! Rutin is a glycoside of quercetin (-> quercetin-3-O-rutinoside) and can be excellent separated from quecertin.