OBJECTIVE or GOAL
Mitigate ionization with sodium.
- All mass spectrometers
- Add a small quantity of ammonium acetate to the mobile phase. The addition of ammonium acetate to the mobile phase minimizes sodium adduct formation. The optimal concentration is approximately 0.5 mM. Higher concentrations of ammonium acetate (1-5 mM) may cause ion suppression.
- Replace methanol in the mobile phase with acetonitrile. Compared with acetonitrile, methanol mobile phase gives a higher degree of adduct formation, particularly for sodium adducts.
1. Rapid Commun. Mass Spectrum. 2009; 23: 1801–1809
2. Pesticides Strategies for Pesticides Analysis, edited by Margarita Stoytcheva; Intechweb.org; page 124
3. Pesticides and their degradation products including metabolites: Chromatography - Mass Spectrometry Methods; Renata Raina-Fulton, Nicole Dunn, Zhen Xie; Intech; page 118