Sensitivity enhancement using nanometer silica particles on the surface of a quartz cell in mercury and selenium determination by vapor generation atomic absorption spectrometry

Abstract

The sensitivity of on-line vapor generation atomic absorption spectrometry of mercury and selenium was improved by using a new atom trap technology. The inner wall of a T-shaped quartz tube was coated with nanometer SiO2 so increase the residence time of the analyte atoms in the light path. The linear range of the calibration plots thus was increased to a range from 5.0 to 150 ng mL−1 for mercury, and from 4.5 to 100 ng mL−1 for selenium. The detection limits are 0.9 ng mL−1 for Hg and 1.0 ng mL−1 for Se which is a 2-fold improvement. The technique was applied to the determination of Hg and Se in herbs and hair.