期刊
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
卷 36, 期 4, 页码 721-727出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.jpba.2004.08.027
关键词
on-line cloud point extraction; capillary zone electrophoresis; dysprosium; iron; urine; MRI contrast agents
Automated preconcentration strategies are needed when analyzing metals in real samples by capillary electrophoresis (CE) with UV detection. The on-line incorporation of cloud point extraction (CPE) to flow injection analysis (FIA) associated with CE for simultaneously determining dysprosium and iron at ppb levels in urine is presented and evaluated for the first time. The preconcentration step is mediated by micelles of the non-ionic surfactant polyethyleneglycol-mono-p-nonylphenylether (PONPE 7.5) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol. The micellar system containing the complex was loaded into the FIA manifold at a flow rate of 8 ml min(-1), and the surfactant rich-phase was retained in a microcolumn packed with cotton, at pH 9.2. The surfactant-rich phase was eluted with 50 mul acetonitrile directly into the CE sample vial, allowing to reach an enrichment factor of 200-fold for a 10 ml sample urine. The type and composition of the background electrolytes (BGE) were investigated with respect to separation selectivity, reproducibility and stability. A BGE of 20 mM sodium tetraborate buffer containing 13% acetonitrile, pH 9.0 was found to be optimal for the separation of metal chelates. Detection was performed at 585 nm. An enhancement factor of 200 was obtained for the preconcentration of 10 ml of sample solution. The detection limits for the preconcentration of 10 ml of urine were 0.20 mug l(-1) for Dy, and. 0.48 mug l(-1) for Fe. The calibration graphs using the preconcentration system were linear with a correlation coefficient of 0.9989 (Dy) and 0.9976 (Fe) at levels near the detection limits up to at least 500 mug l(-1). The method was successfully applied to the determination of dysprosium and iron in urine for monitoring the elimination of dysprosium-based pharmaceuticals. (C) 2004 Elsevier B.V. All rights reserved.
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