|Mei, Ni - Shanghai Institute For Food And Drug Control|
|Liu, Jixin - Chinese Academy Of Agricultural Sciences|
|Mao, Xuefei - Chinese Academy Of Agricultural Sciences|
Submitted to: Spectrochimica Acta B
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2017
Publication Date: 9/12/2017
Citation: Chen, G., Lai, B., Mei, N., Liu, J., Mao, X. 2017. Mercury speciation by differential photochemical vapor generation at UV-B vs. UV-C wavelength. Spectrochimica Acta B. https://doi.org/10.1016/j.sab.2017.09.007.
Interpretive Summary: Mercury is highly toxic, and organic mercury is more toxic than its inorganic counterpart. A low-cost, effective method was developed to differentiate and quantify these two species. After preparation, the ample solutions were mixed with a reductant solution, and then sequentially exposed to ultraviolet (UV)-B or UV-C light. The resulting mercury vapor was detected by atomic fluorescence spectrometry (AFS). The signal intensity depends on concentrations of both inorganic and organic mercury. Two such equations enabled quantitation for both mercury species. This method was applied to fish oil analysis, and gained cost, green chemistry, and throughput advantages.
Technical Abstract: Photochemical vapor generation (PVG) is a simple, low-cost, and effective sample introduction scheme for compounds of volatile mercury (Hg). In this work, speciation of Hg(++) and MeHg(+) in fish oil supplement was fulfilled by differential PVG under two ultraviolet (UV) wavelengths. After extraction induced by emulsion breaking, the sample solution was mixed with 0.4% anthranilic acid-20% formic acid in a flow injection mode in a quartz reactor coil, and exposed sequentially to 311 nm or 254 nm UV light. The resulting mercury vapor was detected by atomic fluorescence spectrometry (AFS). The AFS intensity at each wavelength was a linear function of Hg(++) and MeHg(+) concentrations; a set of two such equations enabled quantitation of both species. This protocol achieved 17 and 14 ng/kg limit of detection for Hg(++) and MeHg(+), respectively, and 73% recoveries at 10 ng/g. Chemical separation was thus obviated leading to cost, green chemistry, and throughput advantages.