title: Dodecylsulfate-coated monolithic octadecyl-bonded silica stationary phase for high-speed separation of hydrogen, magnesium and calcium in rainwater.
abstract: The high-speed determination of hydrogen, magnesium and calcium ions by ion chromatography (IC) is demonstrated on a monolithic octadecyl-boned silica (ODS) column coated with lithium dodecylsulfate (Li-DS). This stationary phase, when used in conjunction with a 2 mM ethylenediamine and 0.1 mM Li-DS solution as eluent at pH 6.0, was found to be suitable for the rapid and efficient separation of hydrogen and magnesium and calcium in the order H+ < Mg2+ < Ca2+ within 4 min at a flow rate of 4.0 ml/min. Under the conditions, linear calibration plots of conductivity versus concentration were obtained for the cations over about three orders of magnitude, and the detection limits were 1 microM for H+, 2 microM for Mg2+ and Ca2+. Rainwater was analyzed directly using this IC system with satisfactory results.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 110, Nishiibara-cho, Seto, Aichi 489-0884, Japan. chemxuqun@yahoo.com
authors.forename: Qun
authors.initials: Q
authors.lastname: Xu
authors.forename: Masanobu
authors.initials: M
authors.lastname: Mori
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Mikaru
authors.initials: M
authors.lastname: Ikedo
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Hu
mesh_terms: D002118:Calcium / Q000302:isolation & purification*; D002845:Chromatography / Q000295:instrumentation* / Q000379:methods; D005029:Ethylenediamines / Q000737:chemistry; D006859:Hydrogen / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000302:isolation & purification*; D011891:Rain; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013997:Time Factors
chemical_list: D005029:Ethylenediamines; D012967:Sodium Dodecyl Sulfate; C031234:ethylenediamine; D012822:Silicon Dioxide; D006859:Hydrogen; C028913:dodecyl sulfate; D008274:Magnesium; D002118:Calcium