USE OF SCAVENGER BEADS TO REMOVE EXCESS LABELING REAGENTS FROM CAPILLARY-ZONE-ELECTROPHORESIS SAMPLES

In many cases, samples for capillary zone electrophoresis (CZE) are de rivatized with a chromophore or fluorophore to enhance their detectabi lity. To ensure efficient labeling, a large excess of labeling agent i s often used, which leads to the presence of a large peak for unreacte d reagent. Here we report that excess reagent can be reacted with ''sc avenger beads'' carrying an appropriate functional group to remove it from the sample solution. We present examples of removal of aminonapht halene mono-, di-, and trisulfonic acid from mixtures in which they we re used to label mono- or oligosaccharides by reductive amination. Ald ehyde-containing scavenger beads were made by oxidizing Sephadex G-50 beads with sodium periodate. These were added to the labeling reaction mixtures after the reductive amination of the sugars was complete. Al most complete elimination of the peak from the labeling agent could be achieved.