Determination of methylmercury and inorganic mercury by volatile species generation-flameless/flame atomization-atomic fluorescence spectrometry without chromatographic separation

Abstract

Volatile species generation-flameless/flame atomization-atomic fluorescence spectrometry (VSG-FL/FA-AFS) without chromatographic separation was developed for quantitative determination of inorganic mercury (IHg) and methylmercury (MeHg) in water and biological samples by using a commercially available atomic fluorescence spectrometer. In the proposed method, inorganic mercury was measured by using the flameless mode. However, by using the flame atomization mode, the volatile hydride of MeHg generated by KBH₄ can be transformed to elemental mercury vapour in the reductive argon–hydrogen flame, and both MeHg and IHg give a fluorescence signal in this flame atomization mode. Then, the concentration of MeHg can be calculated by subtracting IHg concentration from the total mercury concentration. The limits of detection for IHg and MeHg were 0.03 μg L⁻¹ and 0.05 μg L⁻¹, respectively. Spiked environmental water samples including seawater, tap water and river water were determined and satisfactory recoveries were obtained for MeHg and IHg. Furthermore, the proposed method was successfully applied to analyze biological certified reference material, TORT-2 (lobster hepatopancreas).