Synthesis Of Novel Sorbents For Solid-phase Extraction And Their Adsorption Properties For Trace Elements In Solution Samples.

In today's society, as technology's progress and economic development, consumption and emissions of heavy metals which caused by industrial production grew a major problem, thus affecting the health of our people is an important respect. Therefore, the accurate determination of trace and ultra trace metals is the most important research for chemical workers. Recently, in such environmental pollution, food and nutrition fields, the study which of toxic trace elements on human health and environmental impact attracts more and more extensive attention by people. Although modern analytical instrumentation has been great process, but because of the low sensitivity and lots of interference elements, it's difficult to analyze trace and ultra-trace element in an actual samples. Therefore, in the analysis process, we offen should use sample pretreatment, which called separation and enrichment before the accurate determination. This requires SPE sorbent materials possess high selectivity and relatively large adsorption capacity, and then use the appropriate method for separation and enrichment of trace elements in the matrix. So, for the purpose of the designing new separation and enrichment of trace components and analysis method, this thesis obtained five kinds of SPE sorbent materials via modifying attapulgite, multi-walled carbon nanotubes and silica gel, and made in-depth study of their selective adsorption. Our work could be divided into four parts:1. Attapulgite was modified with asparagine and (E)-2-(4-(dimethylamino)-benzylidene)-hydrazinecarbothiohydrazine after it was activeted with the silane coupling agent, and used them for separation and enrichment of trace amounts of Fe(III) and Au(III). The separation/enrichment conditions of analytes, which include the effects of the pH, the sample flow rate and volume, the elution condition, detection limits and precision and the interfering ions on the recovery of the analytes were investigated in detail. The accuracy of the proposed each method was checked by analyzing standard reference material with satisfactory results.2. Multi-wall carbon nanotubes were modified with diethylenetriamine (EDA), and used for separation and enrichment of trace amounts of Cr(III), Fe(III) and Pb(II), and achieved good results. Compared with multi-walled carbon nanotubes, this material improved significantly adsorption selectivity and capacity. 3. Utilizes zincon-modified multiwalled carbon nanotubes as a solid phase extractant has been developed for simultaneous enrichment trace Cr(â…¢),Cu(â…¡),Fe(â…¢) and Pb(II) prior to the measurement by ICP-AES. The conditions, functions of separation and enrichment were investigated in detail. We set up the corresponding analysis method. The method has been applied for the determination of Cr(â…¢),Cu(II),Fe(III) and Pb(II) in water samples with satisfactory results.4. Silica gel was modified with 2-(4-hydroxy-3-methoxybenzylidene)-hydrazinecarbothioamide. And then using the new material for separation and enrichment of trace amounts of Er(III) and Sc(III). This method disply high sensitivity and good selectivity, was used in analysis of environmental samples with good results.