Determination of bromadiolone and brodifacoum in human hair by liquid chromatography/tandem mass spectrometry and its application to poisoning cases.

RATIONALE

Bromadiolone and brodifacoum, two common anticoagulant rodenticides, are involved in the majority of anticoagulant rodenticide poisoning cases in humans in China. Hair analysis can provide long-term information on drug exposure. A method using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) was developed and validated for the measurement of bromadiolone and brodifacoum in human hair.

METHODS

A 1 mL aliquot of a phosphate buffer solution (pH 6.8) was added to 20 mg of pulverized hair followed by ultrasonication and liquid-liquid extraction. Liquid chromatography was performed using a C(18) column with a mobile phase gradient of ammonium acetate (10 mM) and methanol. A tandem mass spectrometer in multiple reaction monitoring mode with a negative electrospray ionization source was employed for detection. Warfarin-d(5) was used as an internal standard for both analytes.

RESULTS

The limits of detection (LODs) for bromadiolone and brodifacoum were 0.010 and 0.025 ng/mg, respectively. The calibration curves for both analytes were linear from 0.025 to 1 ng/mg. The accuracy ranged from 90.3 to 109.3%, and the intra-day and inter-day imprecisions were less than 15%.

CONCLUSIONS

The established method was found effective when applied to the analyses of bromadiolone or brodifacoum in five cases, indicating that segmental hair analysis could be useful for clinical and forensic purposes by identifying the time of ingestion.