Department of Analytical Chemistry, Faculty of Marine and Environmental Sciences, University of Cadiz, 11510 Puerto Real, Spain.
Talanta. 2013 Jan 15;103:161-5. doi: 10.1016/j.talanta.2012.10.026. Epub 2012 Oct 12.
A bulk liquid membrane-flow injection (BLM-FI) system has been developed for the preconcentration and spectrophotometric determination of vanadium in saline waters. The preconcentration step was based on a bulk liquid membrane containing Aliquat 336 (acting as a carrier) dissolved in dodecane/dodecanol. Vanadium species were chemically pumped due to the pH gradient between the sample (pH 3.2) and the receiving solution (pH 9.8). Vanadium transport through the membrane was monitored by a new and sensitive spectrophotometric method based on its reaction with di-2-pyridyl ketone benzoylhydrazone (dPKBH) in an acidic medium. As a consequence of membrane transport, vanadium was recovered in an ammonium solution, where total vanadium concentration was spectrophotometrically determined at 375 nm, as the pentavalent species, by using a flow injection analysis (FIA) system. Under optimal conditions, this FIA system provided a detection limit of 4.7 μg L(-1) (3s(blank)/m) and RSD 2.72%, for vanadium determination in saline samples. Both preconcentration and determination steps were previously optimized by modified simplex methodologies. The proposed coupled method was successfully applied to the determination of vanadium in a certified reference material (TMDA-62) and in two seawater samples.
已开发出一种用于盐水中钒的预浓缩和分光光度测定的 bulk liquid membrane-flow injection (BLM-FI) 系统。预浓缩步骤基于含有 Aliquat 336（作为载体）的 bulk liquid membrane，其溶解在十二烷/十二醇中。由于样品（pH 3.2）和接收溶液（pH 9.8）之间的 pH 梯度，钒物种被化学泵送。钒通过膜的传输通过基于其在酸性介质中与二-2-吡啶酮苯甲酰腙（dPKBH）反应的新的和敏感的分光光度法进行监测。作为膜传输的结果，钒被回收在氨溶液中，其中总钒浓度在 375nm 处通过流动注射分析（FIA）系统作为五价物种进行分光光度测定。在最佳条件下，该 FIA 系统在盐水中钒的测定中提供了 4.7μg L(-1)（3s(空白)/m）的检测限和 2.72%的 RSD。预浓缩和测定步骤均通过改进的单纯形方法进行了优化。所提出的耦合方法成功地应用于测定 TMDA-62 标准参考物质和两个海水样品中的钒。
