Forskning ved Københavns Universitet - Københavns Universitet


Direct on-line analysis of neutral analytes by dual sweeping via complexation and organic solvent field enhancement in nonionic MEKC

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

  • Jun Cao
  • Bin Li
  • Yan-Xu Chang
  • Ping Li
Conventionally, neutral compounds cannot be separated by nonionic micelle capillary electrophoresis. In this report, the development of a novel on-line preconcentration technique combining dual sweeping based on complexation and organic solvent field enhancement is applied to the sensitive and selective analysis of three neutral glucosides: ginsenoside Rf, ginsenoside Rg1, and ginsenoside Re. Nonionic micelle detectability by CE is demonstrated through effective focusing of large sample volumes (up to 38% capillary length) using a dual sweeping mode. This results in a 50- to 130-fold improvement in the LODs relative to conventional injection method. Neutral compounds sweeping is examined in terms of analyte mobility dependence on borate complexation, solvent viscosity difference, and Brij-35 interaction. Enhanced focusing performance by this hyphenated method was demonstrated by a greater than fourfold reduction in glucoside bandwidth, as compared with common sweeping (devoid of organic solvent-mediated sweeping method in the sample matrices). Moreover, separation efficiencies greater than a million theoretical plates can be achieved by sweeping large sample volumes into narrow zones. The designated method was also tested for its ability to determine the presence of glucosides in the crude extracts obtained from plant sample.
Udgave nummer8
Sider (fra-til)1372-9
Antal sider8
StatusUdgivet - 2009
Eksternt udgivetJa

ID: 38008292