离子液体作为新型光度增敏剂测定食品中微量铝(Ⅲ)

建立以离子液体溴化十四烷基咪唑盐(C14 minBr)作为新型光度增敏剂测定食品中铝(Ⅲ)含量的方法。在pH值为4.8的Britton-Robinson缓冲液中，离子液体C14 minBr对Al3+-铬天青体系具有增敏作用，形成Al(Ⅲ)-CAS-C14minBr三元配合物，并在621nm波长处有最大吸收，铝的质量浓度在0.001～0.150μg/mL范围内符合朗伯比尔定律，表观摩尔吸光系数ε621=1.942×105L/(mol·cm)。将该法用于粉丝与粉皮中微量铝的测定，结果与火焰原子吸收光度法测定结果一致，回收率在97.8%～101.8%之间。

Determination of Trace Aluminum in Foods by Ionic Liquid Sensitized Sepctrophotometic Method

A new ionic liquid sensitized sepctrophotometic method was developed on the basis of the Al(Ⅲ)-chromeazurol S (CAS)-1-n-tetradecyl-3-methylimidazolium (C14minBr) system. In the presence of Britton-Robinson buffer solution at pH 4.8, the color reaction of Al(Ⅲ) with chromeazurol S (CAS) could be sensitized by the addition of ionic liquid, C14minBr. The maximum absorption wavelength of the stationary ternary complex Al(Ⅲ)-CAS-C14minBr was 621 nm and the apparent molar absorption coefficient of the complex was 1.942 × 105 L/(mol?cm). Beer’s law was obeyed for Al(Ⅲ) in the range of 0.001–0.150 μg/mL. The developed method was used for the determination of vermicelli and could result in the consistent results from flame atomic absorption spectrophotometry. The recovery rates in the spiked samples were in the range of 97.8%–101.8%.