Determination of Trace Iron in Mongolian Medicine by Ion Exchange Resin Phase Spectrophotometry

Under the buffer medium of HAc-NaAc pH=5,Fe(Ⅱ) and 2,2'-bipyridine formed a colored complex which can be quantitatively absorbed on the strong acidic cation exchange resin,and the amount of trace Fe(Ⅱ) was determined by spectrophotometry.The maximum absorption wavelength is at 522 nm,the apparent molar absorptivity is 9.12×104L·mol-1·cm-1,which is about 11 times than water phase method.The Beer's law is obeyed in the range of 0—1.5mg·L-1 for Fe(Ⅱ).The proposed method has been applied to the determination of trace Fe(Ⅱ) in Mongolian medicine Hasu-12 with satisfactory results.The relative standard deviation is 2.3% and recovery is 98.4%—100.3%,respectively.