The use of Liquid Chromatography-Mass Spectroscopy to Determine Specific Second-Generation Rodenticide Diastereomer Ratios Within Wildlife Liver Samples: The Pursuit Towards a Safer Bait Formula

A recently published master’s thesis from UC Davis discusses rodenticide diastereomers in wildlife liver samples. Liver samples from both targeted and non-target wildlife were analyzed for this project. Non-target species included coyotes, gray foxes, and cougars. The student used chicken liver for the control. Samples were analyzed for the cis and trans isomers of bromadiolone and brodifacoum. The data indicate that secondary poisoning of predators is common.

Liver samples, QC, and calibrants were weighed at 1.0 ± 0.2 g. in a 50 mL centrifuge tube. Each centrifuge tube received deuterated internal standards of each analyte and stainless steel balls. The tubes were shaken for 5 minutes at 750 RPM on a GenoGrinder. Each tube received 6 mL of 10% methanol in acetonitrile. Magnets were used to remove the steel balls, and the samples were shaken for 30 minutes on a wrist-action shaker at its maximum setting. The tubes were then centrifuged for 5 minutes at 2500 RPM at room temperature. The supernatants were collected and added to 15 mL dSPE centrifuge tubes containing 175 mg of MgSO₄, 50 mg Florisil^® PR, and 50 mg of Alumina B (ECQUUS1215CT). The tubes were briefly vortexed and returned to the wrist-action shaker for 30 minutes. Supernatants were transferred to clean test tubes and [presumably] evaporated to dryness at 30-50ºC on an N-Evap Analytical Evaporator. After reconstituting with 1 mL of methanol, the samples were vortexed and sonicated. Each sample was filtered using a Millex-GV Filter, 0.22 µm into clean test tubes. The samples were diluted 10:1 in HPLC vials and briefly vortexed to mix.

An Agilent Technologies 1290 Infinity II High-Performance Liquid Chromatograph paired with a Sciex 7500 QTRAP with Optiflow Pro Ion Source was utilized for analysis.

 

 

David, H. M. (2022). The use of Liquid Chromatography-Mass Spectroscopy to Determine Specific Second-Generation Rodenticide Diastereomer Ratios Within Wildlife Liver Samples: The Pursuit Towards a Safer Bait Formula. UC Davis. ProQuest ID: David_ucdavis_0029M_21467. Merritt ID: ark:/13030/m5s25cvv. Retrieved from https://escholarship.org/uc/item/9j85b245