concentration expressed as "equivalent"

[csolaz]

Hello,

I have a group of compounds (A,B,C...) but standards are no available, so I use a reference compound (R) (commercially available, from the same chemical group) for building a calibration curve and then to quantify A, B, C... expressing their concentrations as "R-equivalents".
How does it work exactly?

this is maybe a too basic-silly question, but I have never worked like this

Thank you in advance

Carmen

[oscarBAL]

Carmen The thing that are you doing depend of the precision that you need for example I did something like that for know the thiner composition, with +/- 1% accuracy, but I would Like to know what detector are you using, what exactly kind of compound you have? because the respond factor depend of the type of detector that you are working.

[csolaz]

Dear Oscar,

thank you for your answer!

I must identify major polyphenolics (there are >5000!!!) in vegetables extracts using standards from each main group of phenolics (5 groups), so I had thought (I read an article) on compare spectres of main unknown peaks to those of standards for knowing if my unknowns are (possibly) polyphenolics (We don't have a LC/MS).

For expressing concentration as the authors did I will use linear curves with standards, but I don't know how they correlate results!

I work with a DAD (PDA) between 200 and 550 nm (+/-).

[oscarBAL]

realy I dont believe that i can help you, your problem is much diferent that I was thinking, but I think that you could identify some caracteristic absortion band where the trancition were from comon groups of your compounds, and supposing that the adsortivy dont chance so much you could use your calibration curve, if not, you should to obtein the response factor, for your main compounds. good luck!

[Uwe Neue]

Here is a subtly different way of going about it: you report the peak areas as measured by your method, and also report the peak area calibration curve(s) of known standards. You may then simply let the reader or the user decide, how valid this is for a quantification of the mass of the unknowns.

[csolaz]

Dear Oscar, Dear Uwe,

Thank you for your answers and ideas!

I'm going to think about them!

Best regards,

Carmen