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Direct UV detection of underivatized amino acids using capillary electrophoresis with online sweeping enrichment
Author(s) -
Jiang Xuemei,
Xia Zhining,
Wei Weili,
Gou Qian
Publication year - 2009
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200900013
Subject(s) - chemistry , chromatography , repeatability , analyte , capillary electrophoresis , amino acid , detection limit , electrospray , electrophoresis , analytical chemistry (journal) , mass spectrometry , biochemistry
This is an original report proposed a CE method for direct analysis of the underivatized amino acids using UV detection with relatively higher sensitivity, which was based on coordination interactions between amino acids and Cu (II) ions. In addition, an online sweeping preconcentration technique was easily combined to improve the detection sensitivity. Satisfying separations of the amino acids were obtained under optimized conditions: 50 mmol/L CuSO 4 –0.05% HAc–H 2 O (pH 4.5), and the separation voltage of 15 kV. The LODs for the analytes ranged from 0.1 to 0.5 μmol/L. The linearity of detection for all analytes was two orders of magnitude with the correlation coefficients greater than 0.99. The repeatability was displayed with an RSD less than 3% for migration time and peak height ( n = 5). Moreover, some amino acids in real samples of human saliva and green tea were analyzed by this direct UV detection CE method with acceptable sensitivity.