硫氰酸钠光度法测定LiFePO_4中的铁

DETERMINATION OF IRON IN LiFePO_4 BY SODIUM THIOCYANATE-SPECTROPHOTOMETRY

研究了硫氰酸钠与铁的显色反应,在pH 1.5左右的酸度下,铁与硫氰酸钠反应形成红色络合物,最大吸收波长为480 nm,表观摩尔吸光系数为7.56×103 L/(mol.cm)。铁含量在300～800μg/(100 mL)范围内符合比耳定律。方法用于LiFePO4中铁的直接测定,测定结果的相对标准偏差为0.8%～1.7%(n=5),标准溶液加入回收率为98.2%～101.9%。

The chromogenic reaction between the sodium thiocyanate and iron was studied. In the medium of pH 1.5 solution, iron reacted with the sodium thiocyanate to form a red complex which exhibited maximum absorption at 480 nm with a apparent molar absorptivity of 7.56 × 10^3 L/（ mol · cm）. Beer＇s law was obeyed in the range of 300 - 800μg/（ 100 mL）. The proposed method was applied to the determination of iron in LiFePO4 with RSD of 0.8% -1.7% （n = 5） and recovery of 98.2% -101.9%.