Fractionation of Pyrene on Fish Gill Surface
用连续提取法研究芘在鱼鳃表面的结合形态

A sequential extraction procedure was developed to investigate the binding status of pyrene on fish gill surface. After exposed to pyrene, fish gills were extracted with H2O, CaCl2, CH3OH and a mixture of n - C6H14 CH2Cl2 (1:1, Accelerated Solvent Extraction) in sequence. The four fractions extracted were the pyrene associated with mucus either loosely or strongly adhered to gill surface, the pyrene sorbed directly on the gill surface and the pyrene accumulated in the gill tissues. The results of a preliminary experiment with five-step CH3OH extraction demonstrated that CH3OH would only strip pyrene bound to the gill surface, rather than those within the gill tissues. After three hours exposure, a large portion of pyrene associated with fish gills were on the gill surface. The percentages of the H2O, CaCl2, CH3OH and n-C6H14 CH2Cl2 extracted fractions were 4.0%, 12.1%, 45.2% and 38.7%, respectively. According to the result of a kinetic- experiment, the partition distribution between the water phase and the gill mucus reached equilibrium around 1 h and the changes in other fractions slowed down remarkably after 3 h.