Abstract: The atomic fluorescence speciation analysis and atomic fluorescence spectrometry were carried out to detect the available selenium in soil at different locations in Enshi City. Extraction conditions such as concentration of leachate,ratio of liquid to sample,shaking time,ultrasonic time,soil fineness,pH of leachate and other conditions were optimized to establish an effective extraction method of available selenium in soil. The extraction method is as follows,after 1.0 g soil sample is weighed into a centrifuge tube,accurately add 10 mL of 0.25 mol/L KH₂PO₄ solution,shaken at 30 ℃,1 500 r/min for 60 min,centrifuged at 3 000 r/min for 15 min. and take 5 mL supernatant for digestion. After digestion,the recovery of the sample was 90.17%~98.00%. It laid the foundation for the development of standards for soil available selenium determination methods.

Key words: atomic fluorescence speciation analysis, atomic fluorescence spectrometry, available selenium in soil, extraction method