Mercury atomic absorption by mercury atoms in water observed with a liquid core waveguide as a long path absorption cell

Abstract

Atomic absorption by mercury atoms in water was observed by using a liquid core waveguide (LCW) as a long pass absorption cell. Mercury atoms in an aqueous solution were generated through mixing a mercury standard solution and a NaBH₄ solution. Atomic absorption spectrum by the generated mercury atoms in the solution was observed. Also atomic absorption by mercury atoms dissolved in water from the gas phase was detected. The observed mercury atomic absorption spectrum has a broadband structure with peak absorption at 255 nm and a bandwidth of 20 nm. The peak wavelength of mercury atomic absorption in water is very close to that of mercury atomic absorption in the gas phase. The bandwidth of mercury atomic absorption in water is much broader than that of mercury atomic absorption in the gas phase, but narrower than that of the absorption spectrum of simple molecules in an aqueous solution. The possible application of this discovery is discussed. Although the absorption cross-section of mercury atomic absorption in water is much smaller than that of mercury atomic absorption in the gas phase, the application of a LCW as a long path absorption cell for detecting mercury atomic absorption in an aqueous solution significantly improved the sensitivity of mercury detection.