在pH 4.3乙酸-乙酸钠缓冲体系中,对乙酰基偶氮氯膦与铝(Ⅲ)形成1∶1蓝紫色络合物,最大吸收波长为604 nm,表观摩尔吸光率ε604 nm=9.92×103L·mol-1·cm-1,铝(Ⅲ)的质量浓度在0.60 mg·L-1以内遵守比耳定律.方法用于方便面、面包及梨中痕量铝的测定,测定结果的相对标准偏差(n=7)在1.03%~2.16%之间,回收率试验的结果在96.5%~101.0%之间.

In an acetate buffer medium of pH 4.3,a blue-violet complex was formed by the reaction of Al(Ⅲ) with p-acetylchlorophosphonazo (abbreviated as CPA-pA) with its molar ratio of 1 to 1. Absorption maxima of the complex was found at the wavelength of 604 nm and its apparent molar absorptivity was 9.92×103L·mol-1·cm-1. Beer′s law was obeyed over the range within 0.60 mg·L-1 of aluminum(Ⅲ). The proposed method has been applied to the determination of aluminum in 3 samples of foodstuff,RSD′s (n=7) values calculated from the analytical results were in the range from 1.03% to 2.16%,and values of recovery found were in the range of 96.5% to 101.0%.