No fumonisin peaks when using new column

[Jasn]

Hi all,

today i had the problem of bad fumonisin chromatography for the second time when installing a new column. The peaks of fumonisins are totally gone or can not be interpreted. The type of column we are using is Hypersil gold 10cm*2.1mm*1.9um from thermo. Mobile phases: A: 2mM NH4FA in water and B: 10mM FA in MeOH. Gradiënt from 95% A to 1%A in 8 minutes. Flow 500ul/min.

What I noticed today is that the problem seems to disappear after injection of 10-20 real matrix samples. After that fumonisin peaks are back and sharp. I presume it might have something to do with the matrix shielding off active sites (free silanols?) or irreversible retention of fumonisins until the active sites are saturated. I wonder what your thought are on this matter and if you have seem similar strange behaviour of fumonisin retention. I'd rather know the cause of the problem because it offers insight on actual mechanisms happening inside HPLC columns.

Thanks for the information!

Kind regards,

Jasper

[Krzykol]

I have approached the same problem with Biphenyl column. After reading your solution a year ago, I have used the same procedure and it worked.

But yesterday the problem have come back. I have lost all peaks for fumonisins (FB1, FB2, FB1_IS), but this time your solution didn't work. What to do now? Can you help me, please?