Sudan Dye in Chilies

[Lynda L]

Hello Everyone,

First of all, thank you all for your experience and advice! I am a frequent viewer of the forum, this is my first post.

Does anyone know of a HPLC method for the determination of Sudan I, II, III, and IV dye in chilie products? I have found a few methods for Sudan I.

I have both a Diode Array and a Fluorescence Detector.

I am also interested in column recomendations for this analysis. I currently have a YMC-ODS-AQ, Synergy Hydro RP, YMC-Pack Polyamine II, and a Zorbax-C8.

Any suggestions or reccomendations appreciated.

Thanks,
Lynda

[Uwe Neue]

A standard reversed-phase column will be fine. I would start off with a gradient with phosphate around pH 2.5 and inject the 4 dye standards. You will find your peaks in a gradient from 5 % to 95 % acetonitrile. Once you know where the peaks elute, you can start the gradient with a higher organci composition etc. Next, you need to get the dyes out of the chili. You need to think about an extraction procedure.

[Mark Tracy]

I did Sudan I, II, III just for show one time. They are surprisingly hydrophobic. I used 50:50:0.5 MeOH:MeCN:AcOH on a 150mm C18 column, and they eluted between 3 and 6 minutes. (That eluent is useful for phenolic antioxidants, and I had some made up, so...)

As for the chili peppers, they have a nice assortment of pigments that are likely to get in the way. You will need your diode array.

[Lynda L]

Uwe and Mark,

Thanks for the response. I will use both your info in my method development!

Lynda