Mercury Speciation in Urban Landfill Leachate by Cold Vapor Generation Atomic Absorption Spectrometry using Ion Exchange and Amalgamation

摘要

This work deals with on line speciation of organic Hg (Hg-org) and inorganic Hg (Hg-inorg) in urban landfill leachate. Chlorocomplexes of Hg-inorg are produced in HCl medium and retained on an anion exchange column. The retained Hg is eluted with NaBH4 in presence of HCl. Hg-0 is produced and then measured by cold vapor atomic absorption spectrometry (CV AAS). Hg-org does not interact with the resin and is mixed with NaBH4 at the exit of the column producing volatile species of Hg that are then amalgamated by a gauze of Au/Pt. Mercury is removed from the gauze by heating to 600 degrees C and subsequently measured by CV AAS. For Hg-inorg and Hg-org speciation in urban landfill leachate, the samples are centrifuged, filtered and treated with HCl. The detection limits (3 s) of Hg-inorg and Hg-org are 9 and 12 ng L-1 of Hg, respectively. The analysis frequency is 22 h(-1).