1-(2-吡啶偶氮)-2-萘酚-6-磺酸光度法高选择性测定乳粉中的微量铁

Study on the spectrophotometric determination of microamounts of iron with 1-(2-pyridylazo)-2-naphthol-6-sulphonic Acid

以 1 (2 吡啶偶氮 ) 2 萘酚 6 磺酸 (PAN S)为显色剂 ,应用分光光度法高选择性测定Fe2 + 。结果表明 ,在pH4 0的乙酸 -乙酸纳缓冲液介质中 ,以 76 0nm为测定波长 ,可高选择性测定Fe2 + 含量。本法线性范围为 0～ 10 μg 10ml,r=0 9997,表观摩尔吸收系数为 1 5 7× 10 4 L·mol- 1 ·cm- 1 ,批内和批间精密度RSD分别为1 6 6 %、2 5 1% ,平均回收率为 10 1 1%。用于乳粉中微量铁的直接测定 。

A new spectrophotometric method has been developed for the highly selective determination of Fe 2+ with 1 (2 pyridylazo) 2 naphthol 6 sulphonic Acid. At pH4 0, Fe 2+ an be selectively determined at the wavelength of 760nm. The calibration curve is liner in a concentration range of 0～10μg/10ml, relative coefficient is 0 9997,the apparent molar absorptivity is 1 57×104L·mol -1 ·cm -1 ,RSD of within run and between day were 1 66% and 2 51%, the average rate of recovery 101 1%. The method has been applied to the direct determination of iron in milk powder, common coexistent substances don′t interfere with the determination.