Studies of speciation and new separation-concentration methods for ultra trace elements in natural water

本文介绍了一种高灵敏、快速、简便的荧光光度测定磷的方法，该方法利用磷钼酸与罗丹明6G形成离子对。当样品溶液在硫酸中调节到0.35moldm~(-3)，在钼酸铵中调节到1.9mmoldm~(-3)，在罗丹明6G中调节到3.1mmoldm~(-3)时，该离子对被收集在由硝酸纤维素制成的膜过滤器上，并在抽吸下通过膜过滤器过滤。膜过滤器和离子对一起溶解于甲基纤维素溶液中。在555 nm处测量了该溶液的荧光强度，激发波长为nm。磷酸盐在5~100 ng范围内线性关系良好(n=12)。虽然砷(V)会引起正误差，但天然水中常见的包括硅酸盐在内的任何离子都不会干扰磷的测定。方法用于水样中磷的测定，…结果令人满意。研究了铜(II)在含2-(水杨叉氨基)硫酚的化学修饰碳糊电极(CMCPE)上的累积伏安行为。在没有外加电位的情况下，铜(II)以络合物的形式在电极上以化学反应的形式积累。观察到了络合物的还原峰。铜(II)在10^&lt；-9&gt；-10^&lt；-7&gt；M范围内呈良好的线性关系，方法适用于美国国家环境研究所研制的标准物质中铜(II)的测定，结果令人满意。此外，通过元素分析和红外光谱对腐植酸的官能团种类进行了鉴定。此外，还考察了离子强度对腐植酸络合铜(II)能力的影响。较少

A highly sensitive, rapid and facile method of fluorophotometry is described for the determination of phosphate using the ion pair formation of molybdophosphate with Rhodamine 6G. This ion pair is collected on the membrane filter made of cellulose nitrate when the sample solution is adjusted to 0.35 mol dm^<-3> in sulfuric acid, 1.9 mmol dm^<-3> in ammonium molybdate and 3.1 mumol dm-3 in Rhodamine 6G, and it is filtered through the membrane filter under suction. The membrane filter together with the ion pair is dissolved into Methyl Cellosolve. The fluorescence intensity of this solution is measured at 555 nm with the excitation at 535 nm. The calibration curve of phosphate is linear from 5 to 100 ng of phosphate(n=12). Although arsenic(V) causes positive error, no ions, including silicate, commonly existing in natural water interfere with the determination of phosphate. The proposed method was applied to the determination of phoshate-phosphorus in water samples and satisfactory resul … More ts were obtained.Accumulation voltammetry of copper(II) at a chemically modified carbon paste electrode(CMCPE) containing 2-(Salicylideneamino)thiophenol was studied. Copper(II) was accumulated as the complex on the electrode based on the chemical reaction without the applied potential. The reduction peak of the complex was observed. The calibration curve of copper(II) was linear over the range of 10^<-9>-10^<-7> M. The proposed method was applicable to the determination of copper(II) in standard reference materials prepared by the National Institute for Environmental Studies, and the results were acceptable.In order to clarify the relation ship between functional groups and copper(II) binding sites in humic acids, pH and conductimetric titration curves of humic acids were compared with those of the model compounds (EDTA, phenylalanine, citric acid and hydroxyhydRoquinone). Moreover, the kinds of functional groups in humic acids were identified by the data obtained from element analysis and FT-IR spectra. Furthermore, effect of ionic strength on the copper(II) complexing abilities of humic acid was investigated. Less