Chromatography Forum

Need some help with a research: Ways to overcome dye peaks overlap in liquid chromatography, appreciate any i get, thanx

Usually dyes are mixtures of isomers. It is also hard to change ionization state of dyes as most of them are based of quaternary amines of sulfates. With mixed mode chromatography you can use two mechanisms to separate your charged compounds:

http://www.sielc.com/Technology_2D_Properties.html

We have few applications for dyes which use this approach. Please check the following newsletter. It has application for mixture of dyes:

http://www.sielc.com/pdf/SIELC_November_2006.pdf

What dyes you are trying to separate?

Regards,

Vlad

First things first, make a trip to the library and read a few of the pertanant books and articles on the subject. Then, if you are still having trouble, maybe think about posting some infromation about what you have done, what you have tried, what compounds you are trying to seperate, and perhaps someone here can provide some ideas and directions to go in.

I recently did FD&C red #40, yellow #5, green #5 and blue #1. These dyes, by the way are all polysulfonated anions. I used a rather complex ion-pairing mobile phase that took a fair amount of tuning. I adjusted the concentrations of organic modifier, tetrabutylammonium ion and ionic strength until I could cluster the related isomers, but separate the colors. It is supposed to be up on the Dionex website in the next few days, but I can send the procedure if you email me at Mark.Tracy@dionex.com