Determination of chlorophacinone and diphacinone in commercial rodenticides by liquid chromatography-UV detection and liquid chromatography-electrospray ionization mass spectrometry.

This work describes a simple method for the determination and mass-spectrometric confirmation of the indanediones in commercial rodenticides. The sample is sonicated in methanol containing 2% formic acid and analyzed by liquid chromatography-UV detection. Once retention time and UV-Vis spectrum provide tentative identification, mass-spectrometric confirmation is obtained by analyzing a second aliquot by LC and electrospray ionization mass spectrometry (LC-ESI-MS). The extensive fragmentation of the indanedione molecule under MS/MS conditions provides sufficient structural information for positive identification on analyte levels as low as 20 ng on column.