Determination Of Trace Noble Metals After Separation And Preconcentration With Nano B₂O₃/TiO₂Composite By Atomic Absorption Spectrometry

Solid-phase extraction （SPE） has been widely used because of its advantages ofhigh selectivity and concentration ratio and so on, coupling with SPE separationtechnology and Atomic spectroscopy （AAS） could efficiently improve the analyticalsensitivity, and the matrix interfere could be effectively reduce or eliminate. While thechoice of adsorb materials which has an important impact on selectivity andsensitivity is the key step in the SPE，therefore，it is a hot research spot to search newand good performance adsorbs materials.On the basis of numerous references, the self-made nanometer B₂O₃/TiO₂composite material and the modified nanometer B₂O₃/TiO₂composite material wereused as solid phase extractor, the performance of adsorption on the trace silver andpalladium with the nanometer B₂O₃/TiO₂and its chemical modification materials wassystematically studied. A new sensitive, efficient and rapid method for the analysisand determination of trace precious metals was proposed.This paper consists of fourchapters; the major contents were described as follows:1. This paper briefly summarized the status and significance of the analysis ofprecious metals, It also introduced the determination method of precious metals，andthe materials and methods of separation/preconcentration of trace precious metals inrecent years were reviewed. Literature focuses on the research and application ofseparation/preconcentration trace precious metals by Nano-oxide, and nanometerB₂O₃/TiO₂composite material as separation/preconcentration material on adsorptionof trace precious metals ion was advanced.2. A new functionalized nanometer B₂O₃/TiO₂composite material was prepared byself. Then the characterization of the synthesized material was performed by SEM, IRand BET. The adsorption behavior of trace silver ions on nanometer B₂O₃/TiO₂composite material were studiedand, the adsorption mechanism of silver to its wasalso discussed. Under the optimal conditions, the static adsorption capacity （Qs） was11.72mg/g. The limit detection of this method （MDL） was found to be2.01μg/L（3, n=11）. The RSD was1.8%. The recoveries in determination slag samples andstandard control sample with satisfactory results.3. By immobilizing4-（2-pyridylazo） resorcinol （PAR） on nanometer B₂O₃/TiO₂composite material with chemical reaction, a new nano-composite material PAR-B₂O₃/TiO₂was prepared. Adsorption property of B₂O₃/TiO₂composite material loaded PAR for trace Ag⁺in the dynamic conditions was investigated. The dynamicadsorption capacity was18.21mg/g. The detection limit of this method（MDL） wasfound to be1.28μg/L L （3, n=11）. The RSD was0.63%. The recoveries of Ag⁺ranged from95.83%to102.13%in determination environment water samples withsatisfactory results.4. Modified nanometer B₂O₃/TiO₂composite material with2-hydroxy benzylrhodanine （2-HBR）, and synthesized （2-HBR）-B₂O₃/TiO₂nano-composites as amicro column material, coupled the flow injection preconcentration with FAAS,Systematically studied the on line preconcentration behavior of trace palladium on（2-HBR）-B₂O₃/TiO₂nano-composites, the optimal experimental conditions wereinvestigated. With the sampling frequency of21h^-1, the enrichment fator is45, andthe sample consumption obtained is0.11mL.The detection limit of this method（MDL） was found to be0.35μg/L （3, n=11）. The RSD was4.19%. It is satisfiedwith the testing of trace Pd2+in environment water.