DEGRADATION OF PENTOBARBITAL IN VARIOUS SOIL TYPES BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY / MASS SPECTROMETRY

Abstract

Pentobarbital is a leading drug for euthanizing large farm animals [Wolfgang et al., 2009]. However, pentobarbital tends to leach into the surrounding soil and become a source of contamination once these euthanized animals are buried. This research was conducted to determine the breakdown rate and extraction efficiency of pentobarbital adsorbed in different types of soil. Additional studies include examining a microbe strain possessing an enzyme capable of breaking down pentobarbital into its metabolites that has leached into the soil.

Solid phase extraction coupled with LC/MS was an efficient method for detecting and quantifying pentobarbital from complex matrices, such as soil. The established method was capable of quantifying 0.5 g of pentobarbital per gram of soil (500 ppb). The soils were spiked with desired amount of pentobarbital and were analyzed daily and weekly to understand the degradation pattern of pentobarbital. In addition, soil samples were autoclaved at 121C to determine if any bacteria caused the degradation of pentobarbital in the soil samples. The finding suggests that the degradation of pentobarbital can be due to microbial influences or nature of the soil or possibly both.