title: An improved ion-exchange/diffusion method for 15N isotope tracing analysis of nitrate in surface waters from watersheds.
abstract: An improved method, suitable for collecting nitrate from surface waters in the watershed for 15N isotope tracing analysis, was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments. The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method. Being simple and practical in operation principle and procedures, cost-economic, and highly efficient in nitrate separation/enrichment, the method met the requirements of delta(15)N mass spectrum analysis and would lay a foundation for the application of 15N isotope tracing approach to the research on non-point source pollution in watershed.
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China. wqchen@xmu.edu.cn
authors.forename: Weiqi
authors.initials: W
authors.lastname: Chen
authors.forename: Weicai
authors.initials: W
authors.lastname: Chen
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Rao
authors.forename: Luoping
authors.initials: L
authors.lastname: Zhang
authors.forename: Huasheng
authors.initials: H
authors.lastname: Hong
mesh_terms: D000327:Adsorption; D000838:Anions; D005591:Chemical Fractionation; D002681:China; D004058:Diffusion; D007474:Ion Exchange; D007475:Ion Exchange Resins / Q000737:chemistry; D007553:Isotope Labeling / Q000379:methods*; D009566:Nitrates / Q000032:analysis*; D009587:Nitrogen Isotopes; D012212:Rheology; D045483:Rivers / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000032:analysis*
chemical_list: D000838:Anions; D007475:Ion Exchange Resins; D009566:Nitrates; D009587:Nitrogen Isotopes; D012996:Solutions; D014867:Water