Analysis of oestrogenic hormones in chicken litter by HPLC with fluorescence detection

摘要

Disposal of animal wastes comprises a primary source of hormones present in the environment. Accurate quantification of hormones in animal wastes is essential to assess the potential risk associated with waste disposal, but represents a significant challenge. In this study, high performance liquid chromatography (HPLC) coupled with fluorescence detection was used to analyse 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in poultry litter. This method involves the use of dichloromethane/methanol (2:1, v/v) mixture to extract the analytes from litter matrix followed by a clean-up procedure using normal-phase open column chromatography to remove lipid contents. Three different types of normal-phase media (commercial silica gel, commercial florisil gel, and self-packed silica gel) were tested and compared for clean-up efficiency. Silica gel was selected and recovery ratios of 73% and 57% were achieved for E2 and EE2, respectively. Detection limits were 4.0 μg/kg and 2.6 μg/kg for E2 and EE2, respectively. Using this method, E2 in stacked broiler litter at different depths and over different stacking times was analysed. It was found that the E2 concentration was as high as 719 μg/kg in the top layer of the litter pile and tends to be lower in deeper layers. We also found that the E2 concentrations decreased significantly over time.