铬蓝黑R-示波计时电位法快速测定天然水不同形态铝  

Determination of Aluminum Fractions in Natural Waters by A.C. Oscillopolarography Using Eriochrome Blue Black R

作　　者：雷建平[1] 干宁[1] 李伟[1] 毕树平[1] 

机构地区：[1]南京大学化学系污染控制与资源化国家重点实验室,江苏南京210093

出　　处：《中国稀土学报》2002年第z2期227-232,共6页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金(No.20075011);国家基础研究(G1999011801);国家教育部重点实验室高级访问学者基金;南京大学分析测试基金资助课题

摘　　要：报道了采用铬蓝黑R(EBBR) 示波计时电位法分别在酸性和碱性条件下直接检测天然水中的无机单核铝[Ali]和总单核铝[Ala]浓度。并用该法测定了酸消化水样中的总铝[AlT],由[Ala]-[Ali]间接得到有机单核[Alo],[AlT]-[Ala]得到酸溶态铝[Alr],从而实现了水中5种Al形态的电化学测定。实验条件和结果如下:在碱性pH=8.0的0.5mol·L-1KCl+0.1mol·L-1Na2B4O7缓冲溶液中,EBBR切口为Ep1=-0.60V,加入铝后出现新切口,Ep2=-1.05V,检测线性范围为5×10-7～7×10-5mol·L-1,检测下限为2×10-7mol·L-1,在5×10-6mol·L-1Al时相对标准偏差为4.6%(n=10)。分别在酸性和碱性条件下测定了水样中的铝浓度,发现在酸性下测定的是无机单核铝,而在碱性下则是总单核铝(包括无机单核铝和有机单核铝两部分)。据此实现了对铝形态的区分,测定了20多个实际水样,与Driscoll方法所获结果进行对照,结果基本一致。Fast determination of five fractions of aluminum in natural waters respectively under acidified and alkalized conditions by a.c. oscillopolargraphy in the presence of Eriochrome Blue Black R (EBBR) was presented. In 0.5 mol·L-1 KCl+0.1 mol·L-1 Na2B4O7 alkaline solution (pH=8.0), 1×10-3 mol·L-1 EBBR yields an incision at the potential of -0.60 V. When Al is added, a new incision appears at -1.05 V. The incision depth of AlEBBR complex is linear with the Al concentration added. The linear range is 5×10-7～7×10-5 mol·L-1 and the detection limit is 2×10-7 mol·L-1. The relative standard deviation (n=5×10-6　mol·L-1 Al) is 4.6%. The Al concentration detected in the alkaline condition was proved to be the total monomeric ［Ala］ (including inorganic monomeric ［Ali］ and organic monomeric ［Alo］) by comparing the results with Driscoll′s speciation method. However, in the acidic condition, the method can only detect the inorganic monomeric ［Ali］. The method was employed to determine five Al fractions in 24 natural water samples.

关 键 词：铬蓝黑R 示波计时电位法 铝形态 天然水 

分 类 号：O657.1[理学—分析化学]