title: Ion-exclusion/cation-exchange chromatography with dual detection of the conductivity and spectrophotometry for the simultaneous determination of common inorganic anionic species and cations in river and wastewater.
abstract: Simultaneous determinations of common inorganic anionic species (SO(4)(2-), Cl(-), NO(3)(-), phosphate and silicate) and cations (Na(+), NH(4)(+), K(+), Mg(2+) and Ca(2+)) were conducted using an ion-chromatography system with dual detection of conductivity and spectrophotometry in tandem. The separation of ionic species on a weakly acidic cation-exchange resin was accomplished using a mixture of 100 mM ascorbic acid and 4 mM 18-crown-6 as an acidic eluent (pH 2.6), after which the ions were detected using a conductivity detector. Subsequently, phosphate and silicate were analyzed based on derivatization with molybdate and spectrophotometry at 700 nm. The detection limits at S/N = 3 ranged from 0.11 to 2.9 µM for analyte ionic species. This method was applied to practical river water and wastewater with acceptable criteria for the anion-cation balance and comparisons of the measured and calculated electrical conductivity, demonstrating the usefulness of the present method for water quality monitoring.
authors.affiliation: Department of Biosphere & Environmental Sciences, Faculty of Environmental Systems, Rakuno Gakuen University, Hokkaido, Japan. nakatani@rakuno.ac.jp
authors.forename: Nobutake
authors.initials: N
authors.lastname: Nakatani
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kozaki
authors.forename: Masanobu
authors.initials: M
authors.lastname: Mori
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hasebe
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Nakagoshi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000838:Anions / Q000032:analysis; D001205:Ascorbic Acid / Q000737:chemistry; D002412:Cations / Q000032:analysis; D002712:Chlorides / Q000032:analysis; D002852:Chromatography, Ion Exchange; D004553:Electric Conductivity; D008672:Metals, Alkali / Q000032:analysis; D008673:Metals, Alkaline Earth / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D017640:Silicates / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet; D013431:Sulfates / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000838:Anions; D002412:Cations; D002712:Chlorides; D008672:Metals, Alkali; D008673:Metals, Alkaline Earth; D009566:Nitrates; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D017640:Silicates; D013431:Sulfates; D014874:Water Pollutants, Chemical; D001205:Ascorbic Acid