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- Posts: 5
- Joined: Wed Mar 13, 2019 3:45 pm
I am having trouble with analyzing and developing a method for glyphosate.
I had the method working and could see glyphosate down to 0.01mg/kg and then all of a sudden the peak deteriorated and I haven't been able to get it back.
I am using a Shimadzu LC stack with the mass spec; Sciex API 4000. An Acclaim Trinity Q1 column 3um 3x100mm (new column)
Mobile phase A: 50mM ammonium formate, formic acid 2.9pH, H2O:ACN 6:4, Mobile phase B:ACN
Gradient Binary Flow: 0 mins 100% A, 10.1 mins 10% A, 13.1 mins 100% A, 18 mins 100% A
Flow rate of 0.5ml/min
(this is from the EU reference glyphosate method: http://www.crl-pesticides.eu/userfiles/ ... urlSRM.pdf)
I prep the samples using the QuPPe method therefore, it is not derivatized.
Since the problem arose, I have made fresh mobile phases and cleaned the ion source. I don't think it's a detection problem as the detector works on other methods.
Does anyone have any idea why it was working and now it is not and how to get it working again? Any help would be appreciated.