光度络合滴定(Ⅱ)——微量铝的滴定(以丙二酸隐蔽铝)

SPECTROPHOTOMETRIC-COMPLEXOMETRIC TITRATIONS (Ⅱ)——THE TITRATION OF MICRO-QUANTITIES OF ALUMINIUM-MALONIC ACID AS MASKING AGENT

本文报导了在室温下以DCTA定量络合铝,并使用DCTA-丙二酸隐蔽法分光光度滴定微量铝的方法。本法的选择性极好。利用这种方法测定了石英石、石英砂、石灰石、白云石和自来水中的微量铝,得到了满意的结果。

We found that malonic acid is a specific masking agent for Al in complexometric titration, and by using the DCTA-malonic acid masking method, Al can be indirectly titrated. This paper reports that 3-100μg of Al (in 35 ml) can be accurately spectro-photometrically titrated with this method at pH5.5 without the interference of the following metal ions: Zr, Th, Sn, Bi, Fe, Ti, Ga, Ce, La, Y, Gd, Cr, Hg, Cu, Ni, Co, Pb, Zn, Cd, Mn, V, Sb, Mo, W, Ca, Mg, etc. The selectivity of the titration is very high. When the Al is titrated at pH3.5 less metal ions will not interfere, but it allows larger amount of Ca and Mg present.This method was successfully used to determine the microquantities of Al in limestone, dolomite, quartz and tap-waters.