PAHs by HPLC-FLD (wavelengths)

[fsistere]

Hi
I’m analyzing PAH’s by HPLC-FLD (fluorescence) in water.

I have a problem with benzo(g,h,i)perylene and indene(1,2,3-cd)pyrene. They elute very close, at 25,8 min and 26,96 min, and their wavelenghts of excitation and emission are different. I have a wavelenght program that it changes the wavelenghts between the two peaks. When the retention times changes a little the wavelength changes in the middle of a peak, and this is a problem.

I can’t resolve better the two peaks ( I worked a lot to resolve them).

Now I’m injecting twice every sample.

The wavelengths are:

Benzo(g,h,i)perylene

Ret. Time (min).- 25.8
Excitation.- 290nm
Emission.- 430nm

Indene(1,2,3-cd)pyrene
Ret. Time (min).- 26.9
Excitation.- 250nm
Emission.- 495nm

Sombody knows other wavelengths that I can use? and if it’s possible the same wavelengths for the two compounds?

Thanks

[HW Mueller]

Run an excitation and emission spectrum. From that you can see whether single wavelengths for both compounds is useful.

[Euro08Soccer]

As far as I remember, I used 300/500 nm for indeno 1,2,3
My advice: change to a column that gives better resolution for the two. Any column manufacturer claims to have one dedicated for PAH, but there are differences. Some of them will give you a test column for evaluation.