NEW UNIVERSAL METHOD FOR DETERMINATION OF ANTICOAGULANTS IN RODENTICIDES

Abstract

Solid paraffin briquettes are one of the most modern types of rodenticide baits, because they protect it from the environmental exposure and do not reduce palatability of rodents. This paper proposes a simple universal method for the determination of brodifacoum, bromadiolone and difenacoum in solid briquettes, which are a mixture of paraffin, poison and filler, which can be used as grain, flour and the like. The difficulty in the analysis of baits containing paraffin, is to get rid of it. For this, we propose to use hexane-acetonitrile extraction in the system. Paraffin dissolves in hexane, while brodifacoum, bromadiolone and difenacoum do not. The resulting two-phase system was separated using a separatory funnel and the bottom fraction was collected. If any fillers were present in the sample, they were filtered until the mixture was separated, the residue was washed with acetonitrile. Before introducing the sample into the chromatograph, it was filtered twice with PTFE filters with a porosity of 0.45 µm. The best separation was achieved using a Thermo Acclaim® Surfactant column using acetonitrile and 0.1 M aqueous ammonium acetate solution (pH 5.4) as the mobile phase in a gradient elution mode. All three poisons were detected at a wavelength of 264 nm. This method has a sensitivity of 0.028 mg. The linearity range is from 0.00067 to 0.01%. The recovery rate for bromadiolone is 94%, for brodifacoum, 98%, and for difenacoum, 90%.