Direct current conductivity detection in ion chromatography

Capillary Scale Admittance and Conductance Detection

“…Design E. This approach uses closely spaced planar electrodes with a circular aperture through which liquid flows, essentially equivalent to two tubular electrodes facing each other, 29 except that the tubes here are ultrashort. In this experiment, both detectors were located after the suppressor, with the admittance detector following cell E. Figure 6 shows the results from cell E and the admittance detector as well as the nonlinear response of the latter linearized by postprocessing of the data.…”

“…In solution conductometry, all possible combinations of two- and four-electrode cells and alternating current/direct current (ac/dc) measurement modes have been reported. − In a four-electrode design, a constant voltage or current is applied between the two outer electrodes, and the resulting current or voltage between the two inner electrodes is respectively measured . The four-electrode approach minimizes detection probe polarization and avoids electrolysis at the detection electrodes, in principle providing greater measurement accuracy …”

Capillary ion chromatography

“…Although not coupled to capillary systems, a variety of electrode/cell designs using small diameter metallic capillaries/needles were described in the literature early on [107]. Thin-walled stainless steel tubes are readily available down to 50 lm in diameter and readily permit making such detectors or detectors of the wall-jet geometry (such as that deployed by Boring et al [78]).…”

Five-electrode direct current suppressor–detector combiner for ion chromatography: an integration of eluent suppression and resistance detection

“…In principle, SIC is based on the addition of a suppressor prior to the conductivity detector (CD) to simultaneously reduce the background conductivity of the eluent and to increase the conductivity detection signals attributable to the sample ions of interest. Although important developments have been made in IC detectors, [2][3][4][5] especially in suppressor technology, [6][7][8][9] the suppressor and detector are separate units in an SIC system, and accordingly the number of components in this system is increased over those nonsuppressed IC systems. [10][11][12][13] This, in turn, increases the complexity of an SIC system and also introduces extra-column volume which may decrease the chromatographic resolution and sensitivity.…”

“…In contrast to the conventional galvanic CDs, 2,4 we have developed a linear equation relating the reciprocal of voltage response of peak height (1/DE) and the reciprocal of concentration of analyte (1/C) for the four-electrode dc resistance detection mode: 17…”