and filtered into vials for RP-HPLC analysis. Diphacinone concentrations were determined using an Aijiren series HPLC system and Gemini C18, 3.0 150mm, 3-mm column (Phenomenex). The aqueous mobile phase was 5mM TBAP in pH 8.5 6mM potassium phosphate, and the organic mobile phase was 5mM TBAP in methanol. For each 30-ml injection,