A novel preconcentration technique using crosslinked chitosan for the determination of mercury by CVAAS

A novel crosslinked chitosan (CCTS) has been synthesized by the reaction of water-soluble chitosan with epoxy chloropropane. In the presence of the chelating EDTA and in the pH range between 4-10, CCTS selectively adsorbed trace inorganic Hg in water samples with enrichment factors of 100. Inorganic Hg could be directly reduced using KBH4 without preceding elution and determined by CVAAS. Accordingly the total mercury could be determined after all species of mercury in water samples were transformed into Hg2+. The detection limit (3 sigma) for mercury was 12 ng L-1 and the relative standard deviation less than 5% at the 50 ng L-1 level. Beer's law was obeyed over the range 30-400 ng L-1 of mercury and the preconcentration method was applied to environmental water samples with the recoveries between 92-96%.