Ion chromatographic separation of common mono- and divalent cations on an unmodified silica gel column by elution with oxalic acid containing crown ethers
- 1 January 1999
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in The Analyst
- Vol. 124 (4) , 505-510
- https://doi.org/10.1039/a808382g
Abstract
An unmodified silica gel (Zorbax BP-SIL) column (150 × 4.6 mm id) was applied to ion chromatography (IC) with conductimetric detection of common mono- and divalent cations (Li+, Na+, NH4 +, K+, Mg2+ and Ca2+). The retention behavior of these mono- and divalent cations on the column under acidic eluent conditions was investigated and it was found that the Zorbax BP-SIL behaved as a cation-exchange stationary phase under acidic eluent conditions and incomplete separation of these mono- and divalent cations was achieved. Therefore, the addition of crown ethers [1,4,7,10,13-pentaoxacyclopentadecane (15-crown-5) and 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6)] to the acidic eluent was carried out for the simultaneous separation of these mono- and divalent cations. Using 1.5 mmol dm–3 oxalic acid–3 mmol dm–3 15-crown-5 as the eluent, both highly sensitive detection and excellent simultaneous separation of these mono- and divalent cations were achieved in 10 min. The proposed IC method was successfully applied to the determination of major mono- and divalent cations in various natural water samples.Keywords
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