Gradient elution capillary electrochromatography and hyphenation with nuclear magnetic resonance

✍ Scribed by Petra Gfrörer; Jens Schewitz; Klaus Pusecker; Li-Hong Tseng; Klaus Albert; Ernst Bayer

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 148 KB
• Volume: 20
• Category: Article
• ISSN: 0173-0835
• DOI: 10.1002/(sici)1522-2683(19990101)20:1<3::aid-elps3>3.0.co;2-u

✦ Synopsis

Coupling of gradient capillary electrochromatography (gradient CEC) and capillary zone electrophoresis (CZE) with nuclear magnetic resonance spectroscopy (NMR) was performed using a recently developed capillary NMR interface. This technique was applied for the analysis of pharmaceuticals and food. An analgesic was investigated using isocratic and gradient continuous-flow CEC-NMR. Comparison of the results demonstrated the superiority of gradient CEC over isocratic CEC. Aspartame and caffeine, both ingredients of soft beverages, were separated and analyzed by continuous flow CZE-NMR. The order of elution could be reversed by altering the pH. This reversal led to an increased sample concentration in the NMR detection cell, thus allowing the acquisition of a totally correlated spectroscopy (TOCSY) two-dimensional (2-D) spectrum of the synthetic peptide aspartame.