Vidotti Eliane C, Almeida Vitor C, Oliveira Cláudio C
Departamento de Quimica, Universidade Estadual de Maringá, Av. Colombo, 5790, DQI, Maringá, PR 87020-990, Brazil.
Talanta. 2004 Nov 15;64(4):993-9. doi: 10.1016/j.talanta.2004.04.018.
A procedure involving bead-injection concept and sequential determination of copper and mercury ions in river-water samples is proposed. The method is based on the solid-phase extraction of both metal ions on the same beads surface (Chelex 100 resin) and in their subsequent reaction with the colorimetric reagents (APDC and Dithizone for copper and mercury ions, respectively). For this task, a resin mini-column is established in the optical path by the selection, introduction and trapping of a defined volume of the Chelex-100 resin beads suspension in the flow system. The passage of the sample solution through the resin mini-column promotes the sorption of Cu(II) ions and, making the APDC colorimetric reagent flows through the beads, the formation of the coloured complex on the solid phase surface occurs. The absorbance of the formed APDC-Cu complex is then monitored at 436nm and the spent beads are discarded. Packing another resin mini-column in the flow cell and repeating the concentration step it is possible to carried out the mercury determination by using Dithizone as reagent. The absorbance of the Dithizone-Hg complex is monitored at 500nm. After each measurement, the spent beads are wasted and a new portion of fresh one is trapped in the system, letting it ready for the next measurement. The bead injection system is versatile and can be used to concentrate different sample volumes, which permits the determination of a wide range of copper and mercury ions concentrations. When the sample-selected volumes are 100 and 1000mul the analytical ranges were 5.0 up to 500.0mugl(-1) and 2.5 up to 30.0mugl(-1) for Cu(II) and Hg(II) ions, respectively. Under these conditions, the detection limit was estimated as 0.63 and 0.25mugl(-1) for copper and mercury ions determination. The system consumes 2mg of Chelex 100 resin beads, 0.20mg of APDC or 1.25mg of Dithizone per determination and the traditional organic solvent extraction methodology, normally used in connection with APDC and Dithizone reagents, is not used here which permits to classify the present method as green.
本文提出了一种基于珠进样概念的程序，用于顺序测定河水样品中的铜离子和汞离子。该方法基于两种金属离子在同一珠表面（螯合树脂100）上的固相萃取，以及它们随后与比色试剂（分别用于铜离子和汞离子的吡咯烷二硫代甲酸铵和双硫腙）的反应。为此，通过在流动系统中选择、引入和捕获一定体积的螯合树脂100珠悬浮液，在光路中建立一个树脂微型柱。样品溶液通过树脂微型柱会促进Cu(II)离子的吸附，当吡咯烷二硫代甲酸铵比色试剂流经珠子时，会在固液表面形成有色络合物。然后在436nm处监测形成的吡咯烷二硫代甲酸铵-铜络合物的吸光度，并丢弃用过的珠子。在流通池中填充另一个树脂微型柱并重复富集步骤，就可以使用双硫腙作为试剂进行汞的测定。在500nm处监测双硫腙-汞络合物的吸光度。每次测量后，废弃用过的珠子，并在系统中捕获新的一部分新鲜珠子，使其为下一次测量做好准备。珠进样系统用途广泛，可用于富集不同体积的样品，这使得能够测定宽范围的铜离子和汞离子浓度。当选择的样品体积为100和1000μl时，Cu(II)和Hg(II)离子的分析范围分别为5.0至500.0μg l-1和2.5至30.0μg l-1。在这些条件下，铜离子和汞离子测定的检测限估计分别为0.63和0.25μg l-1。该系统每次测定消耗2mg螯合树脂100珠、0.20mg吡咯烷二硫代甲酸铵或1.25mg双硫腙，并且此处未使用通常与吡咯烷二硫代甲酸铵和双硫腙试剂相关联的传统有机溶剂萃取方法，这使得本方法可归类为绿色方法。
