Separation And Enrichment Properties Of Modified ?-cyclodextrin On Trace Heavy Metals

On the basis of large domestic and foreign references, triethylenetetramine modified ?-cyclodextrin crosslinked resins(TETA-?-CDP) and maleamic acid crosslinked ?- cyclodextrin polymer(PM-?-CD) have been synthesized by modified ?- cyclodextrin in this paper. The two compounds were applied to the separation and enrichment of trace heavy metal ions as adsorption materials; It has systematically studied the process of separation and enrichment on trace lead, cadmium and silver with TETA-?-CDP and PM-?-CD by hyphenated technique of atomic absorption spectrometry(FAAS) with solid-phase extraction(SPE), and then a new method was established with high efficiency analysis of trace heavy metal. The main contents of the paper were divided into four chapters as follows:1. The paper described the significance and development of the analysis of trace heavy metal elements and summarized the detection methods of heavy metal elements and the separation and enrichment techniques; It mianly introduced the structural properties, modification methods and their applications in separation and enrichment of ?- cyclodextrin.2. A novel ?-cyclodextrin cross-linking polymer(TETA-?-CDP) was synthesized from ?-cyclodextrin which was crosslinked with epichlorohydrin and then modified with triethylenetetramine(TETA). The synthesized material was characterized by infrared spectrometer(IR). Its separation and preconcentration properties for the trace cadmium were studied. The adsorption capacity was 31.4 mg/g. The adsorbed cadmium on the resins could be eluted with 0.5 mol/L HNO3, The detection limit was 27.9 ng/m L(3?, n=11). The liner range was from 0.05 ?g/m L to 2.50 ?g/m L, and the relative standard deviation(RSD) was 1.9%. The method was applied to the determination of trace cadmium in slag samples with satisfactory results.3. In the dynamic conditions, the adsorption properties of TETA-?-CDP resin on trace lead and cadmium were studied by using TETA-?-CDP as the solid phase adsorbent and FAAS as the testing method. The optimum experimental conditions for the separation and concentration were identified, therefore a new method for the simultaneous separation and preconcentration of trace lead and cadmium was established. The dynamic adsorption capacity of lead and cadmium were 22.8 mg/g and 31.3 mg/g. The detection limit of lead and cadmium were 38.0 ng/m L and 16.0 ng/m L(3?, n=11). The method was applied to the determination of trace lead and cadmium in rice samples with satisfactory results. The recoveries of lead and cadmium were between 97.5% ~ 101% and 95.0% ~ 102.5%.4. A modified ?-cyclodextrin polymer(PM-?-CD) was prepared by using self-made maleamic acid(MA) to modify the cyclodextrin and then characterized by BET and FT-IR. With PM-?-CD as the stationary phase and FAAS for the detection,the separation and preconcentration properties of PM-?-CD on trace silver was discussed under the dynamic conditions. The dynamic adsorption capacity was 12.8 mg/g, and the detection limit was 1.68 ng/m L(3?, n=11). The method was successfully used to the separation and enrichment of silver in water.