An ion-exchange/atomic absorption method for the measurement of ionized calcium and magnesium at micromolar concentrations
作者:
Amitha K. Hewavitharana,
Byron Kratochvil,
期刊:
Canadian Journal of Chemistry
(NRC Available online 1993)
卷期:
Volume 71,
issue 1
页码: 17-20
ISSN:0008-4042
年代: 1993
DOI:10.1139/v93-002
出版商: NRC Research Press
数据来源: NRC
摘要:
A quantitative ion-exchange/atomic absorption method is described for measuring the concentration of free (hydrated) calcium and magnesium in solution at micromolar levels. Sample solutions are pumped through a micro-column of strong acid-type cation-exchange resin until equilibrium has been achieved between resin and solution. After removal of interstitial solution by first air, then water, the sorbed metal ion is eluted from the resin with nitric acid directly into an atomic absorption spectrophotometer. In a 0.1 M 1:1 electrolyte, here KNO3, the amount of metal ion sorbed on the resin is directly proportional to the free metal ion concentration in solution over a concentration range of 1.25 to 5 × 10−5 mol/L (12–50 μmol/L). Selectivities for free calcium and magnesium in the presence of complexing ligands such as citrate and phosphate compare well with calculated values.
点击下载:
PDF
(225KB)
返 回