Synthesis of Cross-Linked Chitosan Resin Possessing Leucine Moiety for the Column Collection/Concentration of Molybdenum and Determination of Molybdenum by ICP-MS, ICP-AES and GFAAS

A chitosan resin possessing the leucine moiety (leucine-type chitosan) was newly synthesized by using the chitosan cross-linked with ethylene glycol diglycidyl ether (EGDE) as a basic material. The adsorption behavior of trace amounts of metal ions on the leucine-type chitosan was systematically examined by packing it in a minicolumn by ICP-MS (inductively coupled plasma mass spectrometry). Molybdenum was adsorbed on the resin quantitatively and was easily eluted with 1 M nitric acid. The optimized pH range was from 1 to 5, and Mo was collected by the chelation mechanism and/or the anion-exchange mechanism. The method was applied to the determination of Mo in sea and river water samples. A pretreatment with the resin could remove the matrix components in seawater. Preconcentration by 100fold was accomplished by a column treatment, which had a sufficient concentration to measure trace Mo in river water samples by ICP-AES (inductively coupled plasma atomic emission spectrometry) and GFAAS (graphite furnace atomic absorption spectrometry): LODs with a 100-fold preconcentration by ICP-AES and GFAAS were 0.007 ng mL^-1 and 0.009 ng mL^-1, respectively, and the RSDs were both within 4.0%.