| Nano silicon, because of its good chemical activity, large surface area, and high adsorption capacity, in terms of chemical, mechanical and biological showed high activity and are widely attention. Its can be used as solid-phase extraction agent.However, under acid condition, nanometer SiO2 easy to conglomerate and loss of activity. In order to overcome this problem, this experiment withγ-aminopropyltriethoxysilane to chemical modification of nano SiO2.Use of the modified nano silica as separation and enrichment of material, by atomic absorption spectrometry for testing means, to preliminary enrichment and determination of palladium in zolpidem tartrate and environmental water samples, thus set up a simple,high efficiency, good selectivity, high sensitivity and accurate new method for the detection of trace palladium.The main contents are as follows:1. Comprehensively summarizes the significance and the method for determination of trace metal elements, made a brief introduction to the commonly used method for the separation preconcentration and adsorption materials, focusing on features,application and preparation methods of nano silicon are discussed in details.2. The preparation of nano silica using sol-gel method, then modified byγ-aminopropyltriethoxysilane. And were characterized by scanning electron microscopic(SEM), infrared spectra(IR), and X-ray diffraction(XRD). Has been systematically studied adsorption of trace palladium under static conditions of modified nano SiO2 by flame atomic absorption spectrometry for the test methods,discusses the optimum adsorption conditions of palladium on the modification of nano SiO2 and saturated adsorption capacity. The method has been applied to determination of palladium in geological standard reference materials(GBW07291)with satisfactory results. It proved that this method have the features of accuracy,sensitive, simple.3. The adsorption properties of trace palladium on modified nanometer SiO2 was studied under the condition of dynamic adsorption performance by graphite furnace atomic absorption spectrometry(GFAAS). Trace palladium in zolpidem tartrate was determined. Optimize the specific testing conditions, and have been carried out to verify the method. In this method, the linear range was from 0.0 to 400.0 ng/mL, the relevant coefficient was 0.9992. The detection limit of the method was 1.48 ng/mL.The average recoveries of samples were between 96.4%-101.4%, The RSD of palladium reference substance solution(100 ng/mL) is 2.6%(n=7). This method is simple, rapid, accurate and precise. It can be applied in the determination of trace palladium in zolpidem tartrate.4. A micro PTEE column packed with prepared modified nano silica had been developed for on-line separation and preconcentration trace of palladium by flame atomic absorption spectrometry. The system research on online under the condition of modified nano silica adsorption of trace palladium. Under the optimum experimental conditions, the calibration curve for palladium was linear in the concentration range from 5 μg/L to 500 μg/L with a correlation coefficient of 0.9987, The detection limits was 0.248 μg/L, the relative standard deviation(RSD) for seven replicate measurements 100 μg/L of Pd(II) solution with volume of 7.5 mL was 1.8 %, The enhancement factors was 45, The sampling frequency(f) was 12/h. Finally, the method was applied to determination of trace palladium in different of environmental water samples with satisfactory results. |
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