Solution cathode glow discharge induced vapor generation of mercury and its application to mercury speciation by high performance liquid chromatography–atomic fluorescence spectrometry

A novel solution cathode glow discharge (SCGD) induced vapor generation was developed as interface to on-line couple high-performance liquid chromatography (HPLC) with atomic fluorescence spectrometry (AFS) for the speciation of inorganic mercury (Hg2+), methyl-mercury (MeHg) and ethyl-mercury (EtHg). The decomposition of organic mercury species and the reduction of Hg2+ could be completed in one step with this proposed SCGD induced vapor generation system. The vapor generation is extremely rapid and therefore is easy to couple with flow injection (FI) and HPLC. Compared with the conventional HPLC–CV-AFS hyphenated systems, the proposed HPLC–SCGD-AFS system is very simple in operation and eliminates auxiliary redox reagents. Parameters influencing mercury determination were optimized, such as concentration of formic acid, discharge current and argon flow rate. The method detection limits for HPLC–SCGD-AFS system were 0.67 μg L−1 for Hg2+, 0.55 μg L−1 for MeHg and 1.19 μg L−1 for EtHg, respectively. The developed method was validated by determination of certified reference material (GBW 10029, tuna fish) and was further applied for the determination of mercury in biological samples.