On-line concentration of neutral analytes by complexation and acetonitrile sweeping in nonionic microemulsion electrokinetic chromatography with direct ultraviolet detection.
To separate and detect neutral solutes in nonionic microemulsion electrokinetic chromatography (MEEKC), a novel method was developed, combining complex formation and acetonitrile (ACN) sweeping. In this report, dynamic borate complexation and on-line sweeping occurred simultaneously during a run. The operating parameters which affected the performance of analyte sweeping in nonionic MEEKC were examined in terms of borate complexation, ACN content, Brij-35 concentration and sample plug length. In addition, the validation of the method included tests of the limit of detection, reproducibility and sensitivity enhancement. 60-110-Fold of magnitude improvement in detection sensitivity for model compounds (ginsenoside Rf, ginsenoside Rb2, ginsenoside Re) using Brij-35 microemulsion was demonstrated. Furthermore, the method was applied to the determination of glucosides in the plant extract.
Cao
Jun
J
Key Laboratory of Modern Chinese Medicines, China Pharmaceutical University, Ministry of Education, Nanjing 210009, China. caojun91@163.com
Yi
Ling
L
Li
Ping
P
Chang
Yan-Xu
YX
D000097:Acetonitriles / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000295:instrumentation* / Q000379:methods*; D005960:Glucosides / Q000737:chemistry / Q000302:isolation & purification*; D013056:Spectrophotometry, Ultraviolet
D000097:Acetonitriles; D005960:Glucosides; C032159:acetonitrile