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Molecularly imprinted SPE and MEKC with in‐capillary sample preconcentration for the determination of digoxin in human urine
Author(s) -
GuijarroDíez Miguel,
Paniagua Gema,
Fernández Pilar,
Crego Antonio Luis,
Marina María Luisa
Publication year - 2012
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201100588
Subject(s) - chromatography , chemistry , solid phase extraction , capillary electrophoresis , detection limit , urine , molecularly imprinted polymer , sample preparation , selectivity , biochemistry , catalysis
Molecularly imprinted solid‐phase extraction ( MISPE ) combined with MEKC was used for clean‐up, preconcentration and determination of digoxin in the presence of its aglycon digoxin (digoxigenin) in human urine samples. In addition, the use of an in‐capillary sample concentration electrophoretic technique by sweeping was investigated to enhance the concentration sensitivity in MEKC . The highly selective, fast and effective sample pretreatment by MISPE along with the preconcentration by sweeping could overcome the low sensitivity of the highly efficient capillary electrophoresis separation with UV detection. The optimization of the variables affecting the separation as well as MISPE conditions procedure was carried out to select the best conditions of selectivity and sensitivity to determine digoxin at low concentration levels in urine. To demonstrate the suitability of the developed method several analytical characteristics (selectivity, linearity, accuracy, precision, and LOD ) were evaluated. Satisfactory results were obtained in terms of linearity ( r > 0.99), recovery (95.4–96.5% with RSD from 1.3% to 2.6%), precision ( RSD from 0.3% to 1.7% for migration times and from 2.1% to 7.3% for corrected peak areas), and sensitivity ( LOD s of 6 μg/L with 5 mL of sample or 1.2 μg/L with 25 mL). The proposed MISPE ‐ MEKC method was satisfactorily applied to the analysis of spiked human urine samples achieving a concentration factor up to 7500‐fold.