Abstract: In order to get the optimum conditions for determination of iron in Pyracanthapolysaccharide-Fe (III) complex (PPC).The effects of O-phenanthroline concentration (w/w,%) and its amount (mL),ascorbic acid concentration (w/w,%) and its amount (mL),reaction time (h) as well as its temperature (℃) on the determination of iron in PPC were investigated.On the basis of single factor experiment,response surface software was used to further optimize the detection conditions of PPC.The results showed that the optimum conditions for the determination of iron content in PPC were as follows:1.5 mL 10% ascorbic acid and 3.0 mL 0.1% O-phenanthroline solution were added successively to the PPC solution of 1.0 mL of suitable concentration,and the absorbance was measured at 510 nm at room temperature after a water bath at 45 ℃ for 2.0 h.The developed method had good reproducibility and reproducibility with a recovery rate of 99.93%,which can be applied to detect iron content in other plant polysaccharide- iron complexes.

Key words: Pyracantha fortuneana, polysaccharide-Fe complex, content determination, response surface optimization