A NOVEL PRECONCENTRATION TECHNIQUE USING CROSS-LINKED CHITOSAN FOR THE DETERMINATION OF MERCURY BY CVAAS

A novel crosslinked chitosan (CCTS) has been synthesized by the reacti on of water-soluble chitosan with epoxy chloropropane. In the presence of the chelating EDTA and in the pH range between 4-10, CCTS selectiv ely adsorbed trace inorganic Hg in water samples with enrichment facto rs of 100. Inorganic Hg could be directly reduced using KBH4 without p receding elution and determined by CVAAS. Accordingly the total mercur y could be determined after all species of mercury in water samples we re transformed into Hg2+. The detection limit (3 sigma) for mercury wa s 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 m ercury and the preconcentration method was applied to environmental wa ter samples with the recoveries between 92-96%.