ONLINE PRECONCENTRATION OF TRIAZINE HERBICIDES WITH TANDEM OCTADECYL CAPILLARIES-CAPILLARY ZONE ELECTROPHORESIS

Fused-silica capillaries having surface-bound octadecyl functions were developed for on-line preconcentration of dilute samples prior to capillary zone electrophoresis. The performance of tandem octadecyl capillaries-capillary zone electrophoresis was evaluated with solutes of environmental significance, e.g., prometon and prometryne. The on-line preconcentration was best achieved when oligomeric octadecyl capillaries having roughened inner walls were employed. The coupled configuration enhanced the detectability in terms of solute concentration by a factor of 10 to 35 as compared to that obtained by capillary zone electrophoresis alone. Large volumes of samples could be introduced without affecting separation efficiency.