Research On Features And Application In Geochemistry Of High-Resolution Continuum Source Atomic Absorption Spectrometry

This paper mainly introduces the special features of high-resolution continumm source atiomic absorption spectrometry (HR-CS AAS), and new analytical methods in geochemistry using HR-CS AAS. There are two parts in this work: special features of HR-CS AAS in comparison to the conventional line source AAS's (LS AAS) and methods of analysis.In constrast to LS AAS, HR-CS AAS has the superior merits concerning continuum background correction, calibration curve, sensitivity, signal-to-noise ratio and limit of detection (LOD).The methods for the analysis of sulfur in plant and coal, and phosphorus in plant and soil by measuring the carbon monosulfide (CS) and phosphorus monoxide (PO) using HR-CS AAS with air/acetylene flame have been proposed. The experimental procedures including the optimized instrumental parameters (the ratio of acetylene to air, the burner height) were studied to eliminate the spectral and chemical interferences. The limit of detection (LOD) achieved for sulfur and phosphorus were 14 mg·L^-1 and 20 mg·L^-1, respectively. Accuracy and precision were verified by analysis of standard reference materials.Using the HR-CS-AAS with air/acetylene flame, five metallic elements in drinking mineral water samples and several essential trace elements for human in soil samples were sequentially detected. Based on the analytical results attained, the distribution pattern of these several essential trace elements was preliminary worked out in Bama, Zhuang Autonomous Region of Guangxi.This paper also developed a calibration method to eliminate the spectral interference of iron in the determination of zinc in iron matrices by a set of three linear equations. The HR-CS AAS was used to determine the iron and zinc sequentially. The result showed that this calibration method could effectively eliminate the interference of iron when the concentration of iron was less than 700 mg·L^-1, but the interference can not be corrected by Zeeman-effect backgound corrction and D₂ backgound corrction system of line source AAS.The molecular absorption of air/acetylene flame and HNO₃ was evaluated by HR-CS AAS.The result showed that the molecular absorption was notable at short wavelengths. The feasibility measuring flame temperature by two-line method using Ga 417.204 nm and Ga 403.2982 nm was verified.