| Atomic absorption spectrometry is an instrumental method on the basis of resonance line absorption of ground state atoms, which is produced by the detected elements. This method has low limits of detection, good selectivity, high precision, and strong anti-interference ability, and it is applied to the determination of ths trace metallic elements in environmental samples extensively.However, sometimes the sensitivity is not enough by using this method in practice, but choosing another kind of more sensitive method may be more expensive. Solvent-extraction is the most effective conventional method widely used in separation science, including metal recovery. So it is necessary to keep the relatively cheap atomic absorption spectrometry instrument left and coupled it with solvent extraction.It has been demonstrated that the biological effect and degree of toxicity depends on the chemical form in which the element is present, chromium is a redox active metal that persists as either chromium (III) or chromium (VI) in the environment, with the toxicity of chromium (VI) 100 times higher than chromium (III). Therefore, it is more meaningful to determine the speciation of chromium than the total chromium. In the first part of the thesis, the speciation of chromium in riversamples by using flame atomic absorption spectrometry coupled to solvent-extraction is successively done, the limit of detection of this method is 0.0007 mg/L.In the second part of the thesis, the application of cellulose in the separation or preconcentration of metal ions in various samples is reviewed, which included detection method for the metal ions, kinds of cellulose, absorption and elution conditions and so on.
|
PDF Full Text Request