substance similarity for calibration of HPLC methode

[Ben_]

Hello folks,

im really sorry to bother you with a somewhat noob question.

For my project i need to establish a offline-analytic (hplc) to determine different extrazellular spezies in a fermentation broth.

So what i would do is, ordering pure substances who i like to determine in the culture fluid, injekt them into the hplc to obtain the specific retention times of the analyte for identification.

The problem is for example that one metabolite who needs to be determined is 3-phenylpropionate. but the pure form is only available as ethyl -3- propionate.

to make it short, does it work?

or long: i reckon that due to the extra ethylgroup the retention time will differ as well as the peak area for a latter inegration so that i come up with a somewhat under-or overestimate of 3-phenylpropionate.

what is the opinion of you hplc-pro's

best regards

ben

....non native english speaker

[Andy F]

Regarding 3-phenylpropionate, the parent acid is freely available, well I found it. Try looking up hydrocinnamic acid.

Hope this helps

[Ben_]

thank you Andy, i found it.

sigam aldrich is killing me , when i entered phenylpropionate it just came up with the ethyl-propionate

-but may somebdy. can tell me how the general approch in such a case is-one just goes with what he gets or you try to modifie the substance acordingly?

[prepcolumn]

thank you Andy, i found it.

sigam aldrich is killing me , when i entered phenylpropionate it just came up with the ethyl-propionate

-but may somebdy. can tell me how the general approch in such a case is-one just goes with what he gets or you try to modifie the substance acordingly?

It is quite optimistic to get true information neither for amount (UV spectrum will change) nor for RT (polarity will change) with analysing ethyl analog instead of phenyl propionate.