Multiresidue analysis of nine anticoagulant rodenticides in serum

A rapid procedure was developed for the determination of nine anticoagulant rodenticides in animal serum by high-performance liquid chromatography (HPLC) with a fluorescence and photodiode array detector (DAD). The anticoagulants coumafuryl, pindone, warfarin, coumachlor, diphacinone, chlorphacinone, bromadialone, brodifacoum, and difethialone were extracted and quantitated simultaneously with this method. Anticoagulants were extracted at pH 5.5 with 5% (v/v) ethanol in ethyl acetate and 1% (w/v) trichloroacetic acid. Sample extracts were subjected to a cleanup on a Florisil solid-phase extraction (SPE) column. Separation was performed with a reversed phase amine-deactivated C-18 column with a gradient of phosphate buffer, acetonitrile, and methanal. The eluent was monitored with the fluorescence detection at an excitation wavelength of 310 nm and an emission wavelength of 390 nm, and the photodiode array detection was set to 325 nm. Recoveries from spiked serum samples at ranges of 0.004-1 ppm were between 73 and 105%. The precision (CV) data range was between 1.6 and 15.6%. Detection limits were between 0.005 and 0.002 ppm for the fluorescence detection and between 0.020 and 0.050 ppm for the photodiode array detection at 325 nm.