Trace Analysis Of Pt, Bi, Ag By Crosslinked Chitosan

Trace element anlysis is the important study field of environmental analytical chemistry. In this thesis ,the derivative of chitin - crosslinked chitsan (CCTS) have been applid to trace element analysis of platinum, bismuth and silver.1. A novel method for the separation and preconcentration of platinum with crosslinked chitosan (CCTS) and determination by graphite furnace atomic spectrometry (GFAAS) has been developed. The adsorption rate of CCTS for Pt (Ⅳ) was 100% at pH 3-4 when the adsorption time was not less than 20min. Pt (Ⅳ) was eluted off from CCTS with 5 mL mixture of 0.5mol/LHCl and 3% thiourea and determined by GFAAS. The detection limit (3 σ, n=6) for Pt (Ⅳ) was 2.51ng/mL and the relative standard deviation was less than 8.4 % . The method was applied to environmental water samples with recoveries of 90-94%.2. A novel method has been described for the preconcentration of Bi (Ⅲ) with CCTS and determination by GFAAS. The adsorption rate of platinum by CCTS is 99.77% at pH=3 when the adsorption time was not less than 30min。 Bi (Ⅲ) was eluted from the crosslinked chitosan with 5mol 1.2% citric acid+0.2mol/L HNO3 and determined by GFAAS. The detection limit (3 σ , n=6) for Bi (Ⅲ) was 0.138 ng/ml and the relative standard deviation was less than 3.07% . The method was applied to environmental water samples with recoveries of 90-93%.3. A new method for the preconcentration of s Ag(Ⅰ) with CCTS and determination by GFAAS. The adsorption rate of silver by CCTS is 99.56% at pH=3 when the adsorption time was not less than 40min。 Ag(Ⅰ) was eluted off from CCTS with 8 ml 0.5mol/L ammonia and determined by GFAAS. The detection limit (3 σ , n=6) for Ag(Ⅰ) was 0.406ng/mL and the relative standard deviation was less than 6.8%. The method was applied to environmental water samples with recoveries of87-90%.