Split-flow injector for capillary zone electrophoresis

A simple construction of a split-flow injector eliminating some common prob lems connected with the use of such devices is described. It consists of a low-pressure pump, an injection valve and a delivery tube in which the sepa rating capillary inlet is fixed. The sample is injected without moving the separating capillary inlet and without interrupting the applied voltage. Th e grounded electrophoretic electrode is close to the injection valve so tha t all metal parts of the injector are kept at a sufficiently low potential. Minimum length and small internal diameter of delivery tube minimizes addi tional sample zone broadening. The effects of some experimental parameters, such as the position of the separation capillary inlet with respect to the background solution flow direction and background solution flow-rate are e xperimentally studied. The injector was tested primarily for the electrokin etic injection. (C) 2000 Elsevier Science B.V. All rights reserved.