铬蓝黑R-示波计时电位法快速测定天然水中不同形态的铝浓度

Fast Determination of Different Forms of Aluminum in Natural Waters by A.C. Oscillochronopotentiometry Using Eriochrome Blue Black R

本文报道铬蓝黑 R-示波计时电位法快速测定天然水中不同形态的铝。在 0 .5mol/L 乙酸 -乙酸铵 - 1× 1 0 - 3mol/L铬蓝黑 R( p H4.6)底液中 ,铝 -铬蓝黑 R铬合物在 - 0 .80 V电位处产生灵敏切口 ,切口深度与铝浓度成正比 ,线性范围为 8× 1 0 - 7～6× 1 0 - 5mol/L,检测下限为 6× 1 0 - 7mol/L,相对标准偏差为 4.8% ( n=1 0 ,4× 1 0 - 5mol/L Al)。应用该法测定了天然水中不同形态的铝浓度 ,并同 Driscoll的 MIBK-GF/AAS法进行了比较 。

Fast speciation of aluminum in natural waters by a.c. oscillochronopotenmetry in the presence of eriochrome blue black R(EBBR) is presented in this paper. In 0.5 mol·L -1 NH 4Ac HAc buffer solution(pH 4.6), Al EBBR complex yields one incision on the d E /d t E oscillogram at the potential of -0.8 V when adding Al in the solution. The incision depth is linearly proportional to the Al concentration in the range of 8×10 -7 ～6×10 -5 mol·L -1 . The detection limit is 6×10 -7 mol·L -1 and the relative standard deviation is 4.8% for 4×10 -5 mol·L -1 Al(n=10). The proposed method has been applied to the direct determination of different forms of Al in natural waters, including total Al, total monomeric Al and inorganic monomeric Al. The results is found to be in good agreement with those obtained by the Driscoll's method.