Direct UV detection of underivatized amino acids using capillary electrophoresis with online sweeping enrichment.
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 CuSO4-0.05% HAc-H2O (pH 4.5), and the separation voltage of 15 kV. The LODs for the analytes ranged from 0.1 to 0.5 micromol/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.
Jiang
Xuemei
X
College of Bioengineering, Chongqing University, Chongqing, China.
Xia
Zhining
Z
Wei
Weili
W
Gou
Qian
Q
D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D009994:Osmolar Concentration; D010936:Plant Extracts / Q000737:chemistry; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry; D012680:Sensitivity and Specificity; D012996:Solutions; D013662:Tea / Q000737:chemistry; D013997:Time Factors; D014466:Ultraviolet Rays
D000596:Amino Acids; D010936:Plant Extracts; D012996:Solutions; D013662:Tea; D003300:Copper