Identification and determination of coumateralyl and coumafuryl in animal tissues by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

A high-performance liquid chromatographic-tandem mass spectrometric (HPLC-MS-MS) method was developed and validated to determine simultaneously coumafuryl and coumateralyl in animal tissues using warfarin as an internal standard (IS). Animal tissue samples were extracted with ethyl acetate and cleaned by Oasis HLB solid-phase extraction (SPE) cartridges. After pretreatment, the separation was performed on a XDB C18 column with an isocratic mobile phase of acetic acid-ammonium acetate (5 mmol l(-1), pH = 4.5)/methanol (30:70, v/v). Detection was carried out on a mass spectrometer by negative electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The calibration curves were linear (r(2) > 0.998) in the concentration range 0.75-100.0 ng g(-1) with a lower limit of quantification of 0.75 ng g(-1) for coumafuryl, and 0.5 ng g(-1) for coumateralyl in liver and kidney samples. Intra-day and inter-day relative standard deviations (RSDs) were less than 8.6% and 10.9%, respectively. Recoveries of coumafuryl and coumateralyl were in the range 81.5-89.5%. The developed assay has been applied to the determination of trace residues of coumafuryl and coumateralyl in animal tissues to investigate suspected poisoning of human and animals.