Superwarfarin poisoning is a growing health problem. A sensitive and reproducible LC-ESI/MS/MS
(liquid chromatography electrospray ionization tandem mass spectrometry) method was developed and
validated for the determination of bromadiolone and brodifacoum, the most commonly used
superwarfarins, in human blood using warfarin-D5 as an internal standard. Bromadiolone and
brodifacoum were extracted from whole blood samples by liquid–liquid extraction with ethyl acetate.
Multiple-reaction monitoring (MRM) was used to detect bromadiolone and brodifacoum using
precursor ! product ion combinations of m/z 525 ! 250 and 521 ! 135, respectively. The calibration
curves were linear (r2 = 0.9999) in the concentration range of 0.5–100.0 ng/mL for bromadiolone and
brodifacoum, with a lower limit of detection of 0.1 and 0.2 ng/mL, respectively, in whole blood. This
method detected trace levels of bromadiolone and brodifacoum in whole blood samples and can be used
in the diagnosis of poisoned human beings.