Direct Detection Of Mercury Atoms In Vapor And Aerosol From Chemical Atomization And Nebulization In Flame Atomic Absorption Spectrometer

Direct chemical reduction atomic absorption spectrometry for the determination of mercury in aerosol at 253.7 nm by using a Y-shaped valve coupled with a conventional atomic absorption spectrometer was reported in this paper. An Hg standard solution and a reducing reagent were aspirated into the Y-shaped valve and mixed in the valve. Then the mixed solution was nebulized into aerosol by air in the chamber. The aerosol was carried to the burner without gas/liquid separation, where mercury atoms in the aerosol (both mercury atoms in gas phase purged out of the solution by air and mercury atoms in fog droplets) were determined without flame (at room temperature). Making using of different hollow cathode lamps as light sources, we detected the non-atomic absorption of the mixed solution at 253.7 nm or 253.7 nm nearby in manner of background. The absorption of background at 253.7 nm was linear with the concentration of Hg standard solution. Because the background absorption caused by scattering of the fog drops and the gaseous phase didn't change with the concentration of Hg standard solution, the special background absorption at 253.7 nm might be caused by something in the mixed solution. Then, we approved that the mixed solution did not cause absorption at other wavelengths, because the absorption signals did not change with the concentration of Hg standard solution. Thus, we believed that the clusters of mercury in the fog drops of the mixed solution such as Hg2,Hg3…Hgn might make non-atomic absorption at 253.7 nm, which could testified the atomic absorption signals determined were partly produced by free mercury atoms in fog drops. In addition, we also studied the influence of temperature on sensitivity. The limit of detection was 0.01 μg ml-1 and 0.013 μg ml-1 in summer and winter, respectively. It is a simple and cost-effective method to determine mercury.