Synthesis of novel chitosan resins for collection/concentration of non-metallic elements

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Non-metallic elements are sometimes dissolving as oxoanions in an aqueous media. Of these, arsenic and selenium form complexes with ligands possessing nitrogen atom(s) as coordinate atoms. I newly synthesized a chitosan resin derivatized with 3,4-diamino benzoic acid by using the cross-linked chitosan (CCTS) as a base material (CCTS-DBA resin). Cross-linking of chitosan was carried out with ethyleneglycoldiglycidylether (EGDE), for not shrinking even in a concentrated acidic solution. Then CCTS was reacted with chloromethyloxylane to form "arm" at amino group and finally introduced 3,4-diamino benzoic acid (CCTS-DBA resin). At first, fundamental characteristics (IR spectra, pKa, capacity etc.) of the resin was tested. Then, the adsorption behavior of trace amounts of elements on the CCTS-DBA resin was examined by the column pretreatment method, following measurement by ICP-MS. The resin could adsorb some metal cations at pH from neutral to alkaline region, and several oxoanion species, … More such as arsenic (V), selenium (IV), and selenium (VI) at acidic region. The CCTS-DBA resin is then applied to the collection/concentration of arsenic (V), selenium (VI), and total selenium (IV, VI) in bottled drinking water, tap water, and river water before their measurement by ICP-MS.The batchwise pretreatment needed for 20 min/1 sample, so that automatically controlled collection/ concentration system for ICP-AES was developed. Elements was collected with small chelating disks and chelating resin with iminodiacetate moiety packed in a line filter. This column was installed in the 6-way valve on the pretreatment system which can be connected on line to ICP-AES. The flow rate was 1 ml min- 1 and conditioning of the chelating disk was carried out by flowing 0.5 M ammonium acetate(pH 5.5) for 2 min, sampling for 5 min and washing for 1 min. Elution was done by passing through 2 M HNO3 at 1.3 ml min-1 for 1 min. Nine elements can be determined with 5.0 ml of sample solution. The enrichment factors were 3・15 times and collection efficiencies were better than 80%. The detection limits(LOD) were from 0.003 for Mn to 0.311 for Bi which were several 10 to 100 times lower than normal LOD of ICP-AES. This automated pretreatment method will successfully applied to the determination of non-metallic elements with CCTS-DBA resin by ICP-AES. Less