Dear network,
Around six months ago we validated nitrosamines method on a Sciex +6500 / Agilent 1290 System and signals were great (Based to FDA method); after this numerous analysis we have done responded according validation.
Recently we are experiencing a contamination for NDBA signal (159 m/z --- 103 m/z) which is presented in every injection with a 2-3 x 10e6 magnitude.
We have tried the following actions in order to clear the contamination without a positive response:
Sciex +6500
-
Agilent UHPLC 1290
- AS injector valve cleaning
- AS module exchange with another UHPLC.
- Full UHPLC cleaning and washing for 14h with acetonitrile: IPA: cyclohexane: dicloromethane (25: 50: 15: 10)
- Colum washed for 7h.
- New column.
Others:
- new mobile phase and diluents preparation from unopened solvents.
Dear Alejandro,
We've had the same problem with you for along time. We validated FDA Six impurities method by LC-HRMS but now there is a NDBA impurity with ex105 magnitude. We have tried all possibilities to avoid peak. We sure that MS source is clean due to its control test. Have you solved this problem and what do you suggest to us. Thank you.
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