SDG分离富集5-Br-PAN-S光度法测定水样中微量铁的研究

Determination of Micro-Quantity Iron in Water with 5-Br-PAN-S by Spectrophotometry

研究了铁 (Ⅱ )与5 -Br -PAN -S的显色条件。在 pH3.5～11的缓冲液中 ,形成1∶2型的稳定配合物 ,配合物的最大吸收峰位于540nm和740nm波长处 ,740nm处的表观摩尔吸光系数(ε=1.90×104L/(mol·cm)。铁量在0～80μg/25mL范围内符合比尔定律。采用巯基葡聚糖凝胶(SDG)分离干扰离子富集铁 ,提高了方法的选择性。

The condition of colour reaction of iron with 1-(5-bromo-2-pyridylazo)-2-naphthol-6-sulphonic acid (5-Br-PAN-S) has been optimized.It has been discovered that iron forms with 5-Br-PAN-S at 1:2 stable complex in pH3.5～11. The maximum absorbance of the complex were at 540nm and 740 nm,respectively with its apparent molar absorptivity of 1.9×104 L/mol·cm at 740 nm.Beer's law was obeyed in a range of 0～80 μg/25mL for iron.The common metal ions were easily excluded by the present method. To enrich iron in water by sulfhydryl dextran gel,both selectivity and sensitivity of the method have been improved.The method has been used to determine microamount of iron in water samples and the gained results were found to be satisfactory.