Conductivity detectors sufficiently small for deployment in capillary analytical systems can be fabricated very simply and reproducibly from commonly available micro assemblies of multiconductor ribbons. It results in a unique geometry for the conductivity detection cell where the fluid does not flow between the electrodes. Interface circuitry for a personal computer (PC)-based bipolar pulse conductance detector is described. The cell can be used with this or commercial detectors. Results obtained with the new cell and electronic design in a suppressed conductometric capillary electrophoresis separation system are presented.
Figure 6. Electropherograms with bifilar wire electrode conductivity detector cells: (a) commercial detector electronics (b) present PC-based detectors. Identification: (1) benzoate, (2) gluconate, (3) iodate, (4) carbonate, (5) sulfamate, (6-7) fluoride, and phosphate, in competely resolved (8) malonate, (9) chlorate, (10) thiocyanate, (11) azide, (12) molybdate, (13) nitrate, (14) nitrite, (15) sulfate, (16) chloride, (17) iodide and (18) bromide. All concentrations are 100-ug/L, except fluoride (50 ug/L). Sample injection 2 s at 5 psi.