Studies Of Trace Cd, Cu, Pb Determined By Flame Atomic Absorption Spectrometry After Separation/Preconcentration With Mesoporous TiO₂

In the process of solid phase extract, choose the separate material was the key step, because it could impact the analysis selectivity and the sensitivity. In this paper, on the base of reading lots of literature, self-made mesoporous TiO₂ material by using hydro-thermal method and the modified mesoporous TiO₂ material was used as adsorption material with the a separation technique of Flame Atomic Absorption Spectrometry (FAAS). Moreover, the separation and concentration behaviors of trace level heavy metals were systematically studied. According to the above, novel methods of determine the trace heavy metals were advanced.The major contents were described as follows:1. The method of separation/preconcentration and kinds of adsorption material in analysis determination were reviewed. The synthesized method, characters and applications in separation/preconcentration of new material mesoporous material were introduced in detail. Finally, a kind of novel adsorption material mesoporous TiO₂ was put forward.2. A new mesoporous adsorption TiO₂ was self-made with hydrothermal synthesis and then it was characterized. Adsorption performance of Cd (II) under the stationary condition was studied by FAAS. The static saturated adsorption capacity(Qs) was 57.8 mg /g. The linear range for Cd was 0.05 5μg/mL, the method of the detection limit was 23.0 ng/mL, and the relative standard deviation (RSD) was 2.0% (n = 7, c = 1.0μg /mL).The recoveries were 94.0 102.5%. It had been applied to the determination of cadmium in mineral samples with satisfactory results.3. Adsorption property of mesoporous TiO₂ for trace Cu in the dynamic conditions was investigated. And the main influencing factors of adsorption and elution on copper were systematically investigated. The dynamic saturated adsorption capacity was 7.50 mg/g, the detection limit 0.698 ng /mL, relative standard deviation was 3.5%.The method was applied to environmental water samples in the recovery between 95.8% 101% and the results were satisfactory.4. Mesoporous TiO₂ loaded 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (PMBP) was synthetise. Adsorption property of mesoporous TiO₂ loaded PMBP for trace Pb (II) in the dynamic conditions was investigated. The dynamic saturated adsorption capacity was 9.86 mg/g, the linear range was 0.1 8.0μg/mL, the detection limit 0.533 ng/mL, relative standard deviation was 1.15%.The methods was applied to environmental water samples in the recovery between 96.0 % to 101% and the results were satisfactory.5. A new method had been developed for on-line separation and preconcentration trace of cadmium with loaded mesoporous TiO₂ by infrared spectrometer(FT-IR) prior to its determination by Flame atomic absorption spectrometry. The adsorption and e the main influencing factors of adsorption and elution on cadium were studied in detail and ascertain the optimization experimental conditions. The detection limit was 2.61 ng /mL, relative standard deviation (RSD) was 1.13% and the recovery was 97.4% to 102%. Finally, the proposed method was applied to the actual trace cadmium of the cigarette samples with satisfactory results.