Daniel Sobhi, Babu Prem E J, Rao T Prasada
Regional Research Laboratory CSIR, Inorganic and Analytical Chemistry, Industrial Estate P.O., Trivandrum 695019, India.
Talanta. 2005 Jan 30;65(2):441-52. doi: 10.1016/j.talanta.2004.06.024.
Palladium(II) ion-imprinted polymer (IIP) materials were synthesized by thermally polymerizing the ternary complexes of palladium(II) with amino (AQ) or hydroxy (HQ) or mercapto (MQ) derivatives of quinoline and 4-vinyl-pyridine. The functional and crosslinking monomers used during polymerization were 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA). 2,2'-Azobisisobutyronitrile (AIBN) and 2-methoxy ethanol were used as the initiator and porogen, respectively. The resulting polymer materials were dried in an oven at 80 degrees C, ground and sieved to obtain IIP particles which were then subjected to leaching with 50% (v/v) HCl to obtain the leached palladium(II) IIP particles. Control polymer (CP) particles were also prepared by following the above procedure described for IIP particles. The CP particles, unleached and leached AQ-based IIP particles were then characterized by IR, XRD and microanalysis studies. Analytical studies such as preconcentration of palladium(II) from dilute aqueous solutions and separation studies in the presence of selected noble and base metals which co-exist with palladium(II) in its ore or mineral deposits were systematically studied using CP and IIP particles and are compared. AQ-based IIP particles gave higher percent extraction and selectivity coefficients compared to HQ- or MQ-based IIP particles. Five replicate determinations of 25mug of palladium(II) present in 500ml of aqueous solution, when subjected to preconcentration and determination by iodide-Rhodamine 6G procedure gave a mean absorbance of 0.104 with a relative standard deviation of 2.25%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5.0mug of palladium(II) per litre. The rebinding studies using AQ-, HQ- and MQ-based IIPs were carried out and were fitted to the different adsorption isotherm models, viz. Langmuir (L), Freundlich (F) and Langmuir-Freundlich (LF). These adsorption models were used for the evaluation of binding parameters and in elucidating the nature and type of bonding in the IIPs. The results of rebinding experiments showed discrimination between the three IIPs based on the donor atoms of the ligands.
通过热聚合钯（II）与喹啉的氨基（AQ）、羟基（HQ）或巯基（MQ）衍生物以及4-乙烯基吡啶形成的三元配合物，合成了钯（II）离子印迹聚合物（IIP）材料。聚合过程中使用的功能单体和交联单体分别是甲基丙烯酸2-羟乙酯（HEMA）和乙二醇二甲基丙烯酸酯（EGDMA）。2,2'-偶氮二异丁腈（AIBN）和2-甲氧基乙醇分别用作引发剂和致孔剂。将所得聚合物材料在80℃的烘箱中干燥，研磨并筛分以获得IIP颗粒，然后用50%（v/v）盐酸进行浸提，得到浸提后的钯（II）IIP颗粒。对照聚合物（CP）颗粒也按照上述IIP颗粒的制备方法制备。然后通过红外光谱（IR）、X射线衍射（XRD）和微量分析研究对CP颗粒、未浸提和浸提后的基于AQ的IIP颗粒进行表征。使用CP颗粒和IIP颗粒系统地研究了诸如从稀水溶液中预富集钯（II）以及在与钯（II）共存于其矿石或矿床中的选定贵金属和贱金属存在下的分离研究等分析研究，并进行了比较。与基于HQ或MQ的IIP颗粒相比，基于AQ的IIP颗粒具有更高的萃取百分比和选择性系数。对500ml水溶液中存在的25μg钯（II）进行五次重复测定，当通过碘化物-罗丹明6G程序进行预富集和测定时，平均吸光度为0.104，相对标准偏差为2.25%。发现对应于空白标准偏差三倍的检测限为每升5.0μg钯（II）。使用基于AQ、HQ和MQ的IIP进行了再结合研究，并将其拟合到不同的吸附等温线模型，即朗缪尔（L）、弗伦德利希（F）和朗缪尔-弗伦德利希（LF）模型。这些吸附模型用于评估结合参数以及阐明IIP中的键合性质和类型。再结合实验结果表明，基于配体供体原子的三种IIP之间存在差异。
