Traditionally, nitrosamines have been analyzed by an ion trap in the MS/MS mode, using chemical ionization (CI) to provide a “soft” ionization of the precursor ion (e.g., U.S. Environmental Protection Agency (EPA) Method 521). Most of these methods require a large volume, 10–20 µL, injection. With the highly sensitive Thermo Scientific™ TSQ™ Duo triple quadrupole mass spectrometer this may no longer be necessary. Using automatic selected reaction monitoring (AutoSRM) software to fully optimize the choice of transitions and collision energies, and decreasing the electron energy to 40 eV to soften the ionization, equivalent detection limits can be achieved.
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