Abstract: Objective To study the percentage clearance of methamidophos in blood sample after hemoperfusion. Methods Methamidophos standard solution were put into the blood samples of healthy subjects, and the blood sample were absorbed by hemoperfusion an enveloping active carbon absorption column. Then the blood samples were extracted by ethyl acetate and the contents of methamidophos were determined by Capillary Gas Chromatography (GC). Results The lowest level of methamidophos in mankind blood measured by this method was 0.05ng. The recoveries of low, middle and high concentrations added were between 92.9% and 102.3%. The relative standard deviations (RSD) were between 3.79% and 4.92%. The percentage clearance was 92.6%～98.3%. Conclusion The poisons were mostly removed from blood after poisons absorption through membrane activated charcoal hemoperfusion and the concentration of methamidophos in blood could be reduced rapidly.

Key words: GC, Hemoperfusion, Percentage clearance, Membrane activated charcoal, Enveloping active carbon