Soliman Ezzat M, Saleh Mohamed B, Ahmed Salwa A
Chemistry Department, Faculty of Science, El-Minia University, El-Minia, Egypt. ezzat
Talanta. 2006 Mar 15;69(1):55-60. doi: 10.1016/j.talanta.2005.08.070. Epub 2005 Dec 13.
Dimethyl sulfoxide (DMSO) was simply immobilized to neutral alumina via quite strong hydrogen bonding between sulfoxide oxygen and surface alumina hydroxo groups. The produced alumina-modified dimethyl sulfoxide (AMDMSO) solid phase (SP)-extractor experienced high thermal and medium stability. Moreover, the small and compact size of DMSO moiety permit high surface coverage evaluated to be 2.1+/-0.1 mmol g(-1) of alumina. Hg(II) uptake was 1.90 mmol g(-1)(distribution coefficient log K(d)=5.658) at pH 1.0 or 2.0, 1.68 mmol g(-1) (log K(d)=4.067) at pH 3.0 or 4.0 while the metal ions Ca(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) showed low values 0.513-0.118 mmol g(-1) (log K(d)<3.0) in the pH range 4.0-7.0. A mechanism was suggested to explain the unique uptake of Hg(II) ions by binding as neutral and chloroanionic species predominate at pH values< or =3.0 of a medium rich in chloride ions. A direct and fast batch separation mode was achieved successfully to retain selectively Hg(II) in presence of other eight coexisting metal ions. Thus, Hg(II) was completely retained; Ca(II), Co(II), Ni(II) and Cd(II) were not retained, while Pb(II), Cu(II), Zn(II) and Fe(III) exhibited very low percentage retention evaluated to be 0.42, 0.49, 1.4 and 5.43%, respectively. The utility of the new modified alumina sorbent for concentrating of ultratrace amounts of Hg(II) was performed by percolating 2l of doubly distilled water, drinking tap water, and Nile river water spiked with 10 ng/l over 100mg of the sorbent packed in a minicolumn used as a thin layer enrichment bed prior to the determination by CV-AAS. The high recovery values obtained (98.5+/-0.5, 98.5+/-0.5 and 103.0+/-1.0) based on excellent enrichment factor 1000, along with a good precision (R.S.D.% 0.51-0.97%, N=3) demonstrate the accuracy and validity of the new modified alumina sorbent for preconcentrating ultratrace amounts of Hg(II) with no matrix interference.
二甲基亚砜（DMSO）通过亚砜氧与表面氧化铝羟基之间相当强的氢键简单地固定在中性氧化铝上。所制备的氧化铝改性二甲基亚砜（AMDMSO）固相（SP）萃取剂具有高热稳定性和中等稳定性。此外，DMSO部分的小尺寸和紧密结构使得其在氧化铝表面的覆盖率较高，经评估为2.1±0.1 mmol g⁻¹的氧化铝。在pH 1.0或2.0时，汞（II）的吸附量为1.90 mmol g⁻¹（分配系数log K(d)=5.658），在pH 3.0或4.0时为1.68 mmol g⁻¹（log K(d)=4.067），而金属离子钙（II）、铁（III）、钴（II）、镍（II）、铜（II）、锌（II）、镉（II）和铅（II）在pH值为4.0 - 7.0的范围内显示出较低的值，为0.513 - 0.118 mmol g⁻¹（log K(d)<3.0）。提出了一种机制来解释在富含氯离子的介质中，当pH值≤3.0时，汞（II）离子以中性和氯阴离子形式结合而独特的吸附情况。成功实现了一种直接且快速的批量分离模式，能够在存在其他八种共存金属离子的情况下选择性地保留汞（II）。因此汞（II）被完全保留；钙（II）、钴（II）、镍（II）和镉（II）未被保留，而铅（II）、铜（II）、锌（II）和铁（III）的保留百分比非常低，分别评估为0.42%、0.49%、1.4%和5.43%。通过将2升双蒸水、饮用水和加标10 ng/L的尼罗河水渗滤过100 mg填充在微型柱中用作薄层富集床的吸附剂，然后通过冷蒸气原子吸收光谱法（CV - AAS）进行测定，来评估新型改性氧化铝吸附剂对超痕量汞（II）的富集作用。基于出色的富集因子1000获得的高回收率值（98.5±0.5、98.5±0.5和103.0±1.0），以及良好的精密度（相对标准偏差R.S.D.% 0.51 - 0.97%，N = 3）证明了新型改性氧化铝吸附剂在预富集超痕量汞（II）且无基质干扰方面的准确性和有效性。
