regarding analyte carry over

[rrm1987]

I am using phenomenex kinetex c18 column for ochratoxin A analysis. Mobile phase(Acetonitrile/2%acetic acid=1:1);Flow rate-1ml/min;

when I used to analyse it I am facing carry over problem. I am not sure what is causing this problem? please help me out from this issue.

[Gerhard Kratz]

Please check your autosampler or injection valve first, than check the Connections from the injection System to the column. It can be caused by extra column effects.