Data acquisition
was performed in selected ion monitoring mode using the
following interface parameters: drying gas (N2) flow of 4 L/min;
nebulizer pressure of 74.7 psi; drying gas and vaporizer temperatures
of 325 C and 425 C, respectively; capillary voltage of 4 kV;
corona current of 4 mA; and fragmentor voltage of 55 eV