| With the rapid development of each field in the society, great progress was also achieved in analytical chemistry. Chemical analysis have developed from qualitative detection for a single element to presently trace and ultra trace detection for different elements in different complex samples, and furthermore to synchronous detection for muti-element. Today, the rapid development of various sciences impels significantly improvement of analysis technology, and instrument analysis technology becomes the leading of analytical chemistry. As an important class of instrument analysis method, spectroscopy analysis technology has been widely used. Before the detection of some trace elements, separation and enrichment method for sample pretreatment which can improve the measuring accuracy are required. The majority of separation and enrichment methods require the adsorbent with high selectivity and large adsorption capacity, and appropriate methods of separation and enrichment need to be established. Therefore, in this thesis, three kinds of new solid-phase extraction materials are synthesized by modification on activated carbon and attapulgite material. A new trace component separation and analysis method is established, and several parameters and selective adsorption properties for the adsorbants are investigated. The work is divided into the following three parts:1. A new solid-phase extractant synthesized by immobilizing N-aminopropyl-(3,4,5-trihydroxy)benzamide on activated carbon was used for separation/preconcentration trace Au(Ⅲ), Pd(Ⅱ) and Pt(Ⅳ) ions in samples prior to detection by inductively coupled plasma atomic emission spectrometry (ICP-AES). Different variables that can affect the adsorption of Au(Ⅲ), Pd(Ⅱ) and Pt(Ⅳ) were optimized including acidity, sample flow rate, volume, elution conditions and potentially interfering ions. The optimal pH value was2.0. The adsorption capacity of the material was195.7,95.1and99.3mg g-1for Au(Ⅲ), Pd(Ⅱ) and Pt(Ⅳ), respectively. Then the adsorbed ions were quantitatively eluted by4.0mL of3.0mol L-1HCl-6%CS (NH2)2solution. The presence of several interfering ions, which existed in high excess, did not interfere in both separation and determination of the noble metal ions. The detection limit of the method (3σ) was7,11and6ng mL-1for Au(Ⅲ), Pd(Ⅱ) and Pt(Ⅳ), respectively. The relative standard deviation (RSD) under optimum conditions was less than3%(n=11). The developed method has been successfully applied for the preconcentration and determination of Au(Ⅲ), Pd(Ⅱ) and Pt(Ⅳ) in actual samples.2. Folic acid chemically modified attapulgite as a new solid phase extractant was used for preconcentration/separation of trace Pb(Ⅱ) prior to detection by inductively coupled plasma atomic emission spectrometry(ICP-AES). The effects of pH, sorbent mass, sample flow rate, eluent concentration, eluent volume and potential interfering ions were studied. The saturated adsorption capacity of lead ion was23.59μmol g-1and the detection limits (36) of the method is0.37μg L-1. The method has been validated by analyzing a certified reference material and applied to the determination of trace Pb(Ⅱ) in road dust samples with satisfactory results.3. Attapulgite was chemically modified by hippuric acid to obtain a new solid phase extractant (ATP-HA). And the novel adsorbent was characterized by infrared spectroscopy and elemental analysis. The adsorbent possessed selective adsorption ability for Er(Ⅲ) ion at pH4. Through optimizing the conditions of sorbent mass. sample flow rate, eluent concentration and volume, a fast and accurate analysis method for the detection of trace Er(Ⅲ) ion was established. The saturated adsorption capacity of Er(Ⅲ) ion was88.62μmol g-1and the detection limits (36) of the method was0.066μg mL-1. The presence of several interfering ions did not interfere with the determination of target ion. Finally, the method was successfully applied for separation, enrichment and detection of Er(Ⅲ) in the certified reference material and actual samples. |
PDF Full Text Request