Single-run ion chromatographic separation of inorganic and low-molecular-mass organic anions under isocratic elution: application to environmental samples.
For the isocratic ion chromatography (IC) separation of low-molecular-mass organic acids and inorganic anions three different anion-exchange columns were studied: IonPac AS14 (9 microm particle size), Allsep A-2 (7 microm particle size), and IC SI-50 4E (5 microm particle size). A complete baseline separation for all analyzed anions (i.e., F(-), acetate, formate, Cl(-), NO(2)(-), Br(-), NO(3)(-), HPO(4)(2-) and SO(4)(2-)) in one analytical cycle of shorter than 17 min was achieved on the IC SI-50 4E column, using an eluent mixture of 3.2mM Na(2)CO(3) and 1.0mM NaHCO(3) with a flow rate of 1.0 mL min(-1). On the IonPac AS14 column, it was possible to separate acetate from inorganic anions in one run (i.e., less than 9 min), but not formate, under the following conditions: 3.5mM Na(2)CO(3) plus 1.0mM NaHCO(3) with a flow rate of 1.2 mL min(-1). Therefore, it was necessary to adapt a second run with a 2.0mM Na(2)B(4)O(7) solution as an eluent under a flow rate of 0.8 mL min(-1) for the separation of organic ions, which considerably enlarged the analysis time. For the Allsep A-2 column, using an eluent mixture of 1.2mM Na(2)CO(3) plus 1.5mM NaHCO(3) with a flow rate of 1.6 mL min(-1), it was possible to separate almost all anions in one run within 25 min, except the fluoride-acetate critical pair. A Certified Multianion Standard Solution PRIMUS for IC was used for the validation of the analytical methods. The lowest RSDs (less than 1%) and the best LODs (0.02, 0.2, 0.16, 0.11, 0.06, 0.05, 0.04, 0.14 and 0.09 mg L(-1) for F(-), Ac(-), For(-), Cl(-), NO(2)(-), Br(-), NO(3)(-), HPO(4)(2-) and SO(4)(2-), respectively) were achieved using the IC SI-50 4E column. This column was applied for the separation of concerned ions in environmental precipitation samples such as snow, hail and rainwater.
Micro and Trace Analysis Centre, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium. agnieszka.krata@ua.ac.be
Agnieszka
A
Krata
Velichka
V
Kontozova-Deutsch
László
L
Bencs
Felix
F
Deutsch
René
R
Van Grieken
D000838:Anions / Q000302:isolation & purification*; D002845:Chromatography / Q000379:methods; D004787:Environmental Pollution / Q000517:prevention & control; D007287:Inorganic Chemicals / Q000302:isolation & purification*; D007475:Ion Exchange Resins; D008970:Molecular Weight; D009930:Organic Chemicals / Q000302:isolation & purification*; D012997:Solvents; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
D000838:Anions; D007287:Inorganic Chemicals; D007475:Ion Exchange Resins; D009930:Organic Chemicals; D012997:Solvents; D014874:Water Pollutants, Chemical