Ehrlish reagent - useful for HPLC ?

[goran123]

Hi,

I would like to use Ehrlish Reagent (p-Dimethylaminobenzaldehyde) for
derivatization of some compounds, followed by RP HPLC. I have no experience of this derivatising agent and would like to have some litr ref
describing its use, limitations, reactivity, compatibility with organics etc.
A limitation is that Ehrlish Reagent is used in a high concentration (2 M) of HCl, but maybe this can be neutralized before injection on the column...

I am grateful for suggestions and references.

Regards,

Goran Karlsson
Octapharma AB
Stockholm

[paraboxa]

Erlich's reagent is used in the investigation of porphyrin's. Mixed in alkali with aminolevulinic acid (ALA) you get a reddish colour. Mixed with porphobilinogen (PBG) in acid you get a magenta colour. I think the bonding chemistry will be similar.

You should be able to get a UV-VIS detection method. If you are having difficulties, try complexing your Erlich's with your compound and do a scanning spectograph to ID the peaks.

As for refs, try searching for porphyrin methods or the Watson-Schwartz method, which is the porphyrin method. Clinical Chemistry or The Annals of Clinical Biochemistry may help.

[Mark Tracy]

It rather depends on what the compounds you have in mind to derivatize. Activated benzaldehyde reagents (Ehrlich's, p-anisaldehyde, vanillin) react with a variety of substances. You can also substitute sulfuric acid.