Study On Determination Of Inorganic Ions In Environmental Water By Atomic Fluorescence Spectrometry

Atomic fluorescence spectrometry (AFS) has been rapidly developed since Winefordner put it forward in 1960's. The advantages of AFS over Atomic Absorption spectrometry (AAS) and Atomic Emission spectrometry (AES), in terms of sensitivity, linear range and spectral interferences, were demonstrated both theoretically and experimentally. Now it is a preferred method for determination of 11 elements such as Arsenic, Selenium, Lead, and Mercury, particularly at ultra-trace concentration levels. The above elements are important for the human health and environmental monitoring because of their toxicity. In recent years there has been increasing interest in the trace determination of these elements in environmental, geographical and food samples. AFS, as a very sensitive and selective method, has become a promising tool for the environmental analysis. The use of hydride generation can separate and pre-concentrate analytes from sample, and thereby reduce or eliminate potential chemical and spectral interferences that commonly were encountered in conventional analysis.In this thesis, we put emphasis on seeking the proper working conditions of atomic fluorescence spectrometer, including instrument parameter, sample treatments, acidity of the medium, linear scope of standard curve, recovery, precision, interferences of other elements, detection limit and so on. We determined several samples taken from different water sources, such as river water, underground water, and industrial waste. Then we made cooperation test with other monitoring center and the good results are obtained. The detection limits for Arsenic, Selenium, Lead and Mercury are 0.08 μg/L, 0.12 μg/L, 0.64 μg/L and 0.0081 μg/L, respectively. Obviously, the sensitivity of the method can meet the demand of current water environmental monitoring, since the surface water environmental quality standard of our country for Arsenic, Selenium, Lead and Mercury are 50 μg/L, 10 μg/L, 10 μg/L and 0.05 μg/L, respectively.In order to save regents and enhance working efficiency, we also studied the simultaneous analysis of two elements (Selenium and Arsenic) with atomic fluorescence spectrometry. The measurement condition and sample treatmentprocess were studied. The results show that the fluorescence of Selenium and Arsenic didn't interfere with each other and these elements can be compatibly determined.