铁(Ⅱ)-硫代巴比妥酸-NO_2^-显色体系树脂相光度法测定微量铁

METHOD FOR DETERMINATION OF IRON BY RESIN PHASE SPECTROPHOTOMETRY WITH IRON(Ⅱ)-THIBARBIURIC ACID-NO_2^- SYSTEM

建立了一种测定微量铁的硫代巴比妥酸-NO2-显色体系树脂相分光光度法。在碱性介质中,铁(Ⅱ)可与硫代巴比妥酸(TBA)-NO2-体系反应形成一种稳定的蓝色配阴离子,其最大吸收波长位于671 nm处。该配阴离子能被阴离子交换树脂完全吸附,且树脂相在671 nm处的吸光度与铁含量在0～15μg/(25 mL)的范围内呈良好的线性关系。将该法应用于水样中微量铁的测定,测定结果与原子吸收光谱法测定结果相吻合,加标回收率为94%～102%,测定结果的相对标准偏差为3.4%～4.8%(n=5)。

A method for the determination of trace iron（ Ⅱ ） in water by the resin phase spectrophotometry with thibarbiuric acid -NO2- was established. In alkalescenee base medium, iron（ Ⅱ ） reacted with thibarbiuric acid - NO2- to form a blue complex anion with absorption peaks at 671 nm, and it could be absorbed entirely by anion exchange resin. Linear relationship between values of absorbance of resin phase and mass concentration of iron was found in the range of 0 - 15.0 μg/（25 mL）. The method was applied to determine trace iron in water, and the result was in good agreement with that obtained by FAAS. The recoveries were 94% - 102% and the relative standard deviation of determination results were 3.4% - 4.8% （ n = 5）.