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甲基百里酚蓝(MTB)光度法测定铝,具有显色pH范围宽、条件易控制等优点,但方法选择性较差。本文对铝-MTB体系在pH5乙酸-乙酸钠缓冲介质中的显色条件及共存元素干扰的消除进行了试验。结果表明,络合物显色后10分钟达完全,并至少稳定4小时;最大吸收波长为525—535nm;0—50微克/50毫升铝范围符合比尔定律。共存元素的干扰可借显色后加入大量EDTA使其褪色予以消除,而络合物不显色。若在显色前加入EDTA,络合物也不显色。据此,用加了EDTA制备的不显色试液为参比测量,可使方
Methyl thymol blue (MTB) spectrophotometric determination of aluminum, with a wide range of color pH, the conditions are easy to control, but the selectivity of the method is poor. In this paper, the conditions for the color development of Al-MTB system in acetic acid-sodium acetate buffer medium pH5 and the co-existence of interference elements were tested. The results showed that the complex reached a complete state at 10 minutes after color development and was stable for at least 4 hours. The maximum absorption wavelength was 525-535 nm. Beer’s law was obeyed in the 0-50 μg / 50 ml aluminum range. The interference of coexisting elements can be eliminated by adding a large amount of EDTA after color development to fade, while the complex does not develop color. If EDTA was added before color development, the complex did not develop color. Accordingly, with added EDTA prepared non-color test solution for the reference measurement, can make square