Approximately 0.8–1.0 g of fresh duodenal midpieces sample and Zn sources were burned until they were of constant weightatwt. measurement at 8157 10 1 C. 0.1 g of the ash was weighed and transferred into a beaker.
Two milliliters of perchloric acid and 10 mL hydrofluoric acid were added to the beaker, and then the beaker was transferred to anoven at 35 1 C for 1 h.
The solution was slowly evaporated and almost dried in an electric heating plate.
The globule on the wall of the beaker was was heddown with a small amount of deionized water, and the solution was evaporated continually until white smoke from the solution disappeared.
After being cooled, 10 mL of 30% hydrochloric acid and 10 mL water were added.
The solution was slowly evaporated to nearly boiling for 20 min and filtered.
The solution was transferred into a 100 mL flask and diluted with water to scale as the stock solution (Sui et al.,2011).
The supernatant was used for determining zinc concentration.
The concentration of zinc was determined according to the instrument working conditions of AAS.